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Hermaphrodite

A hermaphrodite is an organism that produces both male (sperm) and female (ova) gametes, either simultaneously or sequentially during its life cycle, enabling reproductive capabilities typically associated with both sexes.^[1] The term derives from the ancient Greek myth of Hermaphroditus, the child of Hermes and Aphrodite who merged with the nymph Salmacis to form a single being with dual sexual characteristics.^[2] In biology, hermaphroditism occurs widely among plants, where many species exhibit self-fertilization via bisexual flowers, and invertebrates such as earthworms and snails, which possess simultaneous hermaphroditism allowing mutual insemination during copulation.^[3] Sequential hermaphroditism, involving sex reversal, is prevalent in certain fish like clownfish, where individuals transition from female to male or vice versa based on social or environmental cues to optimize reproduction.^[4] Among vertebrates, functional hermaphroditism is rare and phylogenetically declining, with no documented cases in mammals beyond aberrant human instances termed true hermaphroditism, characterized by the coexistence of ovarian and testicular tissue in a single individual, often presenting with ambiguous genitalia and accounting for fewer than 10% of disorders of sex development.^[5]^[6] These conditions in humans typically arise from genetic mosaicism or chimerism, such as 46,XX/46,XY karyotypes, and pose challenges for fertility and gender assignment due to incomplete gonadal functionality.^[7] While adaptive in low-density populations for ensuring mating opportunities, hermaphroditism generally yields lower evolutionary fitness compared to gonochorism (separate sexes) in higher-density species, reflecting a trade-off in resource allocation between dual reproductive roles.^[3]

Etymology

Linguistic Origins

![Statue of Hermaphroditus][float-right] The term "hermaphrodite" originates from the name of Hermaphroditus, a figure in Greek mythology depicted as the offspring of the gods Hermes and Aphrodite, who became fused with the nymph Salmacis to embody both male and female characteristics.^[8] This mythological narrative, detailed in Ovid's Metamorphoses around 8 CE, provided the foundational concept for the word, reflecting an androgynous being rather than a biological classification.60188-8/fulltext) Linguistically, the Greek proper name ἑρμαφρόδιτος (hermaphróditos) is a compound derived from Ἑρμῆς (Hermês, Hermes) and Ἀφροδίτη (Aphrodítē, Aphrodite), signifying a union of paternal and maternal divine attributes.^[2] The term entered Latin as hermaphroditus, retaining its mythological connotation of dual sexual traits, before being adopted into Middle English in the late 14th century.^[9] The earliest recorded English usage appears in John Trevisa's 1398 translation of Bartholomaeus Anglicus's De Proprietatibus Rerum, where it described individuals possessing attributes of both sexes.60188-8/fulltext) This transmission preserved the term's etymological link to ancient myth, distinct from later scientific applications in biology.^[2]

Historical and Scientific Usage

The term "hermaphrodite" derives from the Greek mythological figure Hermaphroditus, the son of Hermes and Aphrodite, who fused with the nymph Salmacis to form a being with both male and female physical characteristics, as recounted in Ovid's Metamorphoses around 8 CE.^[2] This mythological origin influenced its adoption in Latin and later European languages, entering Middle English by 1398 through John Trevisa's translation of Bartholomaeus Anglicus's De Proprietatibus Rerum, where it described individuals exhibiting combined male and female traits.60188-8/fulltext) In ancient Roman contexts, the term was applied to intersex individuals, often viewed as divine omens or punishments, with legal and social implications for gender assignment.^[10] During the Renaissance and into the 17th century, European societies permitted those classified as hermaphrodites to select their gender role, reflecting a pragmatic approach rather than strict binary enforcement.^[11] By the 18th century, Enlightenment-era medical discourse largely rejected the possibility of true human hermaphroditism, deeming it incompatible with rational anatomy and favoring explanations rooted in developmental errors over mythical duality.^[12] In the 19th century, clinicians adopted a gonadal criterion, categorizing hermaphrodites among five sex types based on the presence of ovarian or testicular tissue, which informed surgical and diagnostic practices amid Victorian efforts to define discrete sexes.^[13] In modern biological science, "hermaphrodite" precisely denotes organisms possessing both male and female reproductive organs capable of producing gametes of both sexes, distinguishing true hermaphroditism (simultaneous functional duality) from sequential forms where sex changes over time.^[14] This usage predominates in non-human contexts, such as simultaneous hermaphrodites like earthworms or sequential ones like certain fish, emphasizing adaptive reproductive strategies over human pathology.^[15] For humans, true hermaphroditism—defined by the coexistence of ovarian and testicular tissue (often ovotestes)—occurs rarely, with asymmetrical gonadal development; however, the term has been largely supplanted since the late 20th century by "disorders of sex development" (DSD) or "intersex" to avoid implications of functional equivalence to invertebrate models and reduce stigma.^[13]^[15] This shift reflects clinical prioritization of chromosomal, hormonal, and anatomical causality over historical morphological labels, though biological texts retain "hermaphrodite" for accurate description in comparative physiology.^[16]

Definition and Biological Principles

Core Definition

A hermaphrodite is an organism that possesses both male and female reproductive organs and can produce both male gametes (sperm) and female gametes (ova), enabling it to function reproductively as either sex or both.^[9]^[16] This condition, termed hermaphroditism, occurs naturally in approximately 30% of animal phyla, particularly among invertebrates such as earthworms and snails, as well as in many plant species and certain fish.^[17]^[18] Unlike gonochoristic species, where individuals are strictly male or female, hermaphrodites may exhibit simultaneous hermaphroditism (both organ sets active concurrently) or sequential hermaphroditism (sex change over time, as in some wrasse fish).^[17] In biological terms, hermaphroditism requires functional duality, meaning the organism can successfully fertilize itself or others using both gamete types, though self-fertilization is rare due to inbreeding risks and often avoided via mechanisms like reciprocal insemination in simultaneous cases.^[17] This reproductive strategy evolves in environments with low population density or high mate-finding costs, enhancing mating opportunities; for instance, in sessile marine invertebrates, it ensures reproduction without mobility.^[19] Empirical studies confirm its adaptive value, with species like the sea slug Crepidula fornicata demonstrating sequential shifts that optimize lifetime fecundity based on size and dominance hierarchies.^[17] True hermaphroditism must be distinguished from pseudohermaphroditism or intersex conditions in vertebrates, especially mammals, where gonadal tissue may be mixed (e.g., ovotestes) but rarely both fully functional for producing viable gametes of each type.^[13] In humans, such cases—historically labeled "true hermaphroditism"—involve 46,XX/46,XY chimerism or mosaicism in about 90% of documented instances, yet physiological limitations prevent dual reproductive success, rendering the term biologically imprecise for mammals and leading to its replacement with "disorders of sex development" in clinical contexts.^[13]^[20] Thus, the core biological usage applies primarily to non-mammalian taxa where dual functionality is empirically verified.^[17]

Types: True, Sequential, Simultaneous, and Pseudo

True hermaphroditism is defined by the presence of both ovarian and testicular tissues in the same individual, either as separate gonads or combined in ovotestes, which may enable the production of both ova and sperm depending on functionality. This condition arises from genetic mosaicism, such as 46,XX/46,XY chimerism, and is exceedingly rare in mammals, including humans, where it represents a disorder of sex development rather than an adaptive trait. In such cases, gonadal asymmetry is common, with one tissue predominating, and fertility is typically limited to one gamete type if present at all.^[21]^[15] Sequential hermaphroditism involves individuals that produce gametes of one sex during early reproductive phases and switch to the opposite sex later in life, optimizing reproductive success in environments where sex-specific roles vary with age, size, or social dominance. This can manifest as protandry, where organisms begin as males before transitioning to females, or protogyny, the reverse, with the switch often triggered by environmental cues, hormonal changes, or removal of dominant individuals in a group. The process is genetically determined but environmentally modulated, ensuring only one sex is functional at a time to avoid self-fertilization conflicts.^[22]^[23] Simultaneous hermaphroditism occurs when an organism maintains both male and female reproductive organs concurrently, capable of producing sperm and ova within the same breeding season, which facilitates self-fertilization or cross-fertilization with conspecifics. This strategy predominates in sessile or low-mobility species, such as certain invertebrates, where encountering a mate is challenging, and it often includes mechanisms like reciprocal insemination to minimize inbreeding depression. Both sets of gametes are typically functional, though selfing rates vary by species and context.^[24] Pseudohermaphroditism describes a phenotypic mismatch where gonads develop as a single sex—either testes or ovaries—but external genitalia or secondary sexual characteristics resemble the opposite sex, resulting from disruptions in hormonal signaling or androgen/estrogen action during development. In male pseudohermaphroditism, testes form but masculinization fails, leading to ambiguous or feminized genitalia; female pseudohermaphroditism involves ovaries with virilized features due to excess androgens. This differs fundamentally from true hermaphroditism by lacking dual gonadal tissues and is observed sporadically in mammals as a developmental anomaly rather than a reproductive strategy.^[25]^[26] Gonochorism denotes a sexual system in which individuals develop as either male or female, producing gametes of only one type—sperm or eggs—and requiring cross-fertilization between opposite sexes.^[27] This contrasts fundamentally with hermaphroditism, where individuals possess and can utilize both male and female reproductive organs to produce both gamete types, either concurrently or successively over their lifetime.^[28] In gonochoric species, sex is often fixed early in development, determined by genetic factors such as XY chromosomes in mammals or ZZ/ZW systems in birds, preventing any individual from functioning reproductively in both roles.^[29] The distinction extends to population-level dynamics and mating strategies. Gonochoristic species typically exhibit sex ratios near 1:1, with males and females specialized for distinct reproductive functions, such as enhanced mobility or parental investment tailored to gamete type.^[30] Hermaphrodites, by comparison, mitigate risks of mate scarcity by self-fertilization potential (though often avoided via outcrossing mechanisms) or bilateral insemination, advantageous in low-density environments where finding unisexual partners proves challenging.^[31] Evolutionary transitions between these systems occur, but gonochorism predominates in vertebrates and many arthropods, while hermaphroditism prevails among mollusks, annelids, and most plants.^[32] Related phenomena include mixed mating systems like gynodioecy or androdioecy in plants, where populations comprise unisexual females (or males) alongside hermaphroditic individuals, blending gonochoric and hermaphroditic elements without pure separation of sexes across all members.^[33] Sequential hermaphroditism further blurs lines with gonochorism in species exhibiting conditional sex change, such as certain reef fish, where initial sex may mimic fixed gonochorism until environmental cues trigger reversal, unlike the irreversible unisexuality of strict gonochorists.^[30] Pseudohermaphroditism, observed in some invertebrates and mammals, involves ambiguous external traits atop unisexual gonads, representing developmental anomalies rather than adaptive dual functionality akin to true hermaphroditism.^[34] These variants underscore that gonochorism enforces discrete, non-overlapping sexual roles, whereas hermaphroditic strategies enable flexibility at the individual level.

Occurrence in Animals

Sequential Hermaphrodites

Sequential hermaphroditism refers to a reproductive strategy in which an individual organism functions as one sex during an early life stage and switches to the opposite sex later, producing male gametes (sperm) initially and female gametes (eggs) subsequently, or vice versa.^[35] This differs from simultaneous hermaphroditism, where both gamete types are produced concurrently, and occurs predominantly in certain invertebrates and fishes.^[36] The two primary forms are protandry, where individuals mature first as males before transitioning to females, and protogyny, where the initial phase is female followed by a change to male.^[37] In protandrous species, such as the common slipper limpet (Crepidula fornicata), juveniles settle as males on stacks of adults, mating with established females before growing larger and changing sex to become females themselves, a process influenced by social cues like population density and body size.^[38] This transition typically occurs as the individual reaches a size threshold, around 15-20 mm in shell length, enabling higher egg production as a larger female.^[39] Similarly, clownfishes (Amphiprion spp.), including Amphiprion ocellaris, begin life as males in hierarchical anemone groups; the dominant breeding female's removal prompts the largest male to undergo sex reversal over weeks to months, involving gonadal restructuring from testes to ovaries and behavioral shifts to female dominance.^[40] Hormonal mechanisms, including elevated estrogen levels, drive this change, ensuring group reproductive continuity.^[41] Protogynous hermaphroditism prevails in many reef fishes, exemplified by parrotfishes (Scaridae family), where most individuals start as females in an "initial phase" and, upon reaching maturity (often 20-30 cm in length), select larger ones transition to colorful terminal-phase males capable of controlling harems or spawning territories.^[42] In species like the stoplight parrotfish (Sparisoma viride), this shift correlates with increased testosterone and body size, allowing dominant males to achieve higher fertilization success through territorial defense rather than small-female egg output.^[43] Fishing pressure can disrupt this by selectively removing larger males, skewing sex ratios and reducing population fecundity.^[44] The adaptive basis for sequential hermaphroditism often aligns with the size-advantage model, positing that fitness gains from sex change exceed costs when reproductive success scales differently with size between sexes—small individuals benefit from the sex with lower size dependency (e.g., male sneaking or female brooding), while larger ones excel in the opposite (e.g., female fecundity or male competition). Empirical studies confirm this in mollusks and fishes, where protandry suits low-male-competition environments and protogyny fits male-controlled mating systems, enhancing lifetime reproductive output by 20-50% over fixed-sex alternatives in modeled populations.^[45] Transitions between protandry and protogyny are rare evolutionarily, with gonochorism (separate sexes) more stable, underscoring sequential forms' niche specificity in sessile or group-living taxa.^[46]

Simultaneous Hermaphrodites

![Mating earthworms][float-right] Simultaneous hermaphrodites possess functional male and female reproductive organs concurrently, enabling the production of both eggs and sperm within the same breeding period.^[24] This condition predominates among certain invertebrate phyla, including Annelida, Mollusca, and Platyhelminthes, where individuals maintain dual gamete production throughout adulthood.^[47] In annelids such as earthworms (Lumbricus terrestris), pairs align antiparallel during copulation to exchange sperm mutually via spermathecae, ensuring reciprocal fertilization without designated sex roles.^[48] Pulmonate gastropods, including garden snails (Helix pomatia), exhibit similar behaviors, often employing love darts—calcareous structures injected to stimulate mucus production and influence post-mating sperm storage—prior to simultaneous insemination.^[49] Platyhelminth flatworms, like Pseudobiceros bedfordi, engage in hypodermic insemination, where partners stab each other's bodies with stylets to inject sperm directly into the partner's tissues, bypassing genitalia and promoting bilateral gamete transfer amid aggressive "penis fencing" contests to avoid the female role.^[50] Among vertebrates, simultaneous hermaphroditism occurs in approximately 15 genera of fish across ten families, such as hamlet groupers (Hypoplectrus spp.), which court partners daily and alternate male and female roles during rapid egg-sperm release sequences, sometimes within minutes.^[51] Other examples include chalk bass (Serranus tortugarum), which form monogamous pairs for mutual fertilization.^[47] This reproductive strategy confers evolutionary advantages in sparse or immobile populations by maximizing mate availability, as any individual can function as both donor and recipient, reducing search costs and enhancing fertilization success rates compared to gonochoristic systems.^[52] However, it entails conflicts over sex allocation, with larger individuals often dominating the male role for higher sperm competitiveness, as observed in seven studied species where male success correlates positively with body size.^[49] ![Mating flatworms][center]

Examples and Adaptive Contexts

In sequential hermaphrodites, prominent examples include the clownfish (Amphiprion ocellaris), which exhibit protandry, starting life as males and changing to females under specific social conditions. Within anemone-hosted groups, a dominance hierarchy exists where the largest individual is female, followed by the breeding male, and smaller non-breeding males; if the female dies, the breeding male transitions to female, with the next largest male assuming the breeding role, ensuring reproductive continuity.^[53] This adaptation aligns with the size-advantage model, wherein larger body size confers greater reproductive success to females through increased egg production, favoring sex change at a threshold size where female fitness exceeds male fitness.^[54]^[55] Another example is the Atlantic slipper limpet (Crepidula fornicata), a protandrous species forming stacked aggregations where smaller individuals atop the stack function as males, mating with females below, and transition to females as they grow and move downward.^[38] Sex change timing is plastic, influenced by social cues like the presence of females and population density, optimizing reproduction in sedentary, filter-feeding lifestyles.^[56] The adaptive benefit here also stems from size-advantage dynamics, as larger females produce more eggs, with empirical data showing male reproductive success peaking early and female success later in ontogeny.^[56] For simultaneous hermaphrodites, earthworms (e.g., species in Lumbricus) possess both ovarian and testicular tissues, exchanging sperm reciprocally during copulation via aligned genitalia, typically avoiding self-fertilization to promote genetic diversity.^[19] This strategy enhances mating opportunities in soil environments where encounters may be infrequent, allowing any pair to fertilize each other fully, though multiple matings can boost cocoon hatching success through sperm competition mechanisms.^[57] Evolutionarily, simultaneous hermaphroditism persists in annelids by balancing selfing risks with outcrossing benefits, particularly in patchy habitats, as it reduces the mate-search costs inherent in gonochoristic systems.^[19]^[58] These examples illustrate how hermaphroditism adapts to ecological constraints: sequential forms leverage ontogenetic growth for sex-specific fitness gains, while simultaneous forms maximize pairwise compatibility, both elevating lifetime reproductive output relative to fixed-sex alternatives in their respective niches.^[54]^[32]

Occurrence in Plants

Monoecy and Functional Equivalents

Monoecy refers to a sexual system in seed plants in which individual plants produce separate unisexual male (staminate) and female (pistillate) flowers or cones on the same organism.^[59] This arrangement enables a single plant to function reproductively as both male and female, analogous to hermaphroditism in animals, though the separation of sexes into distinct floral structures distinguishes it from plants bearing perfect (bisexual) flowers containing both stamens and pistils.^[60] In angiosperms, monoecy typically arises developmentally from an ancestral hermaphroditic state through the spatial segregation of sexual functions, often via genetic mechanisms that suppress one sex's organs in specific flowers.^[61] Among angiosperms, monoecy occurs in approximately 7% of species, a frequency slightly exceeding that of dioecy (separate sexes on different plants) and reflecting its evolutionary persistence despite pathways toward sexual specialization.^[60] Common examples include maize (Zea mays), where male tassels emerge at the apex and female ears develop lower on the stem; oaks (Quercus spp.), birches (Betula spp.), and walnuts (Juglans spp.), which bear catkins or nuts accordingly; and crops like squash (Cucurbita pepo) and hemp (Cannabis sativa).^[62] ^[63] These systems often incorporate temporal or spatial mechanisms to mitigate self-fertilization, such as staggered maturation of male and female flowers in maize, where pollen shedding precedes silk receptivity by days, favoring outcrossing via wind or insects.^[64] Functional equivalents to monoecy encompass other monomorphic systems where both sexual roles are consolidated within one individual, notably cosexuality via perfect flowers, which predominate in over 90% of angiosperm species and allow combined male-female function in unified structures.^[65] Unlike monoecy's unisexual flowers, perfect flowers integrate both organs, but both strategies yield adaptive benefits in sparse populations by ensuring reproductive assurance—self-compatibility when mates are scarce—while permitting outcrossing to enhance genetic diversity.^[66] Empirical studies indicate monoecy evolves recurrently from hermaphroditism, sometimes as a transient state en route to dioecy, driven by selection for sex allocation efficiency, such as allocating resources to male function early in flowering and female later.^[61] This flexibility supports higher seed set in variable environments, as observed in wind-pollinated monoecious trees where male flowers are numerous and ephemeral to maximize pollen dispersal.^[62]

Andromonoecy and Gynomonoecy

Andromonoecy refers to a sexual system in plants where individuals bear both staminate (male-only) flowers and hermaphroditic (bisexual) flowers.^[67] This condition occurs in approximately 1.7% of angiosperm species, representing around 4,000 species distributed across 33 families, with notable prevalence in lineages such as the grass subfamily Panicoideae and the Cucurbitaceae family.^[68] Examples include watermelon (Citrullus lanatus), where andromonoecy is controlled by a major gene influencing flower sex expression, and muskmelon (Cucumis melo subsp. melo), in which plants produce male flowers early in development followed by hermaphroditic ones.^[69]^[70] Other instances occur in Passiflora incarnata, where male flowers exhibit superior pollen export compared to hermaphroditic counterparts, potentially enhancing male reproductive success.^[71] Evolutionarily, andromonoecy facilitates size-dependent resource allocation, prioritizing female function in larger plants while using less costly male flowers for pollen dissemination under pollen limitation or developmental constraints.^[72]^[60] Gynomonoecy, conversely, involves the co-occurrence of pistillate (female-only) and hermaphroditic flowers on the same plant.^[73] This system is less frequent across angiosperms, estimated at about 3% of species and documented in roughly 23 families, though it is disproportionately common in the Asteraceae family.^[74]^[75] Representative examples include species in the genus Anacyclus (Asteraceae), where gynomonoecy follows Mendelian inheritance patterns, and Silene noctiflora, in which up to 90% of individuals under certain conditions express female flowers alongside hermaphroditic ones to modulate selfing rates.^[73]^[76] In mycoheterotrophic orchids like Eulophia zollingeri, gynomonoecy supports mixed mating strategies in nutrient-limited environments.^[77] Adaptive benefits may include reduced pollen-pistil interference, increased outcrossing via female flowers, and higher offspring fitness from pistillate-derived seeds, potentially stabilizing the system against invasion by pure hermaphrodites or full dioecy.^[74]^[78] Both systems represent intermediate states between pure hermaphroditism and monoecy, allowing flexible sex allocation in response to environmental cues like resource availability or pollinator behavior, though andromonoecy predominates due to the lower energetic cost of male relative to female structures.^[79]^[60]

Evolutionary Patterns in Angiosperms

Hermaphroditism, in which individual flowers produce both male and female gametes, represents the ancestral and most prevalent sexual system among angiosperms, with phylogenetic analyses reconstructing the most recent common ancestor of flowering plants as possessing cosexual flowers.^[80] This system predominates, occurring in the majority of angiosperm species, though exact proportions vary by taxonomic scale and life form, with hermaphrodites comprising roughly 70-90% depending on whether species or genera are considered.^[65] The evolutionary lability of sexual systems in angiosperms is evident from repeated transitions among hermaphroditism, monoecy, and dioecy, facilitated by genetic mechanisms such as sex chromosome evolution and nuclear-cytoplasmic conflicts.^[81] Transitions from hermaphroditism to dioecy, the separation of sexes into distinct individuals, have occurred independently over 100 times across the angiosperm phylogeny, often via intermediate states like gynodioecy (coexistence of females and hermaphrodites) or monoecy (separate male and female flowers on the same plant).^[82] Monoecy itself evolves frequently from hermaphroditism, serving as a stepping stone to dioecy in some lineages, though reversals to hermaphroditism are also documented, indicating that dioecy is not an evolutionary dead end.^[65] Phylogenetic comparative studies highlight that such shifts correlate with ecological factors, including pollination efficiency and mating opportunities, where hermaphroditism persists or reemerges when selfing rates are low and mate availability is limited.^[83] Geographic and climatic patterns further illuminate evolutionary dynamics: hermaphroditism is more frequent in warm, arid tropics, while dioecy and monoecy increase toward higher latitudes, potentially driven by historical climate fluctuations influencing transition rates.^[84] For instance, transitions between hermaphroditism and dioecy accelerated under warmer paleo-temperatures exceeding certain thresholds, whereas monoecy transitions declined.^[85] Differences between woody and herbaceous growth forms underscore adaptive contexts, with woody species showing higher dioecy proportions in temperate zones, possibly due to longer lifespans allowing specialization.^[86] Polyploidy events, common in angiosperms, associate with shifts toward subdioecious systems but less so with pure hermaphroditism, suggesting whole-genome duplications facilitate sexual system diversification.^[87] Overall, these patterns reflect a balance between the reproductive assurance provided by hermaphroditism—reducing mate-finding costs in sparse populations—and selective pressures favoring unisexuality to mitigate inbreeding or pollen discounting in dense, pollinator-rich environments.^[61] Empirical genomic data from genera exhibiting mixed systems confirm high evolvability, with supergene complexes underpinning rapid shifts without fixation barriers.^[81]

Occurrence in Other Organisms

Fungi and Mating Types

In fungi, sexual reproduction is regulated by mating types rather than dimorphic sexes, with compatibility governed by idiomorphs (alleles at mating-type loci, or MAT) that encode transcription factors controlling developmental genes for plasmogamy, karyogamy, and meiosis.^[88] Homothallism and heterothallism represent the primary systems, where homothallism functions as a form of hermaphroditism by enabling self-fertile sexual reproduction within a single genetic individual or spore-derived culture, often through mechanisms like initial haploid selfing, pseudohomothallism (balanced diploid spores with both mating types), or mating-type switching.^[89] ^[90] This self-compatibility contrasts with anisogamous hermaphroditism in animals but achieves similar outcomes in mate assurance, particularly in sparse populations where outcrossing partners are rare.^[91] Heterothallism, by comparison, imposes outcrossing requirements akin to gonochorism, mandating plasmogamy between compatible hyphae of differing mating types to avoid self-fertilization and promote genetic diversity via recombination.^[90] Bipolar heterothallism involves a single MAT locus with two idiomorphs (conventionally denoted + and -), yielding binary compatibility, as seen in many Ascomycota like Neurospora crassa, where self-incompatibility enforces heterozygosity at MAT until karyogamy.00730-9) Tetrapolar systems, prevalent in Basidiomycota such as Coprinopsis cinerea, feature two unlinked loci (often A and B), generating thousands of mating-type combinations—up to 12,000 in some species—through multiallelic variation, which maximizes outcrossing potential while allowing rare selfing if mutations occur.^[92] Homothallism has arisen independently over 50 times across fungal phyla, often via gene duplications or rearrangements at MAT loci that enable intra-individual mating, as evidenced by comparative genomics in Ascomycota and Mucoromycota.^[93] In Saccharomyces cerevisiae, homothallic strains employ a HO endonuclease to switch mating types during mitotic growth, facilitating immediate self-diploidization after meiosis, a mechanism absent in heterothallic relatives.^[94] These systems reflect adaptations to ecological pressures: homothallism mitigates Allee effects in colonizing or low-density niches, as in obligately sexual homothallic species like the rice blast pathogen Magnaporthe oryzae, while heterothallism sustains variability against pathogens via negative frequency-dependent selection on rare mating types.^[91] Empirical studies confirm homothallic lineages exhibit reduced effective population sizes due to inbreeding, paralleling selfing costs in hermaphroditic taxa.^[95]

Invertebrates and Protists Beyond Standard Categories

Many invertebrate phyla, including Annelida, Mollusca, and Platyhelminthes, commonly exhibit simultaneous hermaphroditism, where individuals possess both ovarian and testicular tissues and typically engage in reciprocal sperm exchange to avoid self-fertilization.^[96]^[97] In earthworms (Oligochaeta, Annelida), pairs align antiparallel during copulation, with each acting as both male and female, transferring sperm via spermathecae for later egg fertilization; this strategy enhances reproductive success in dense soils where encounters are frequent but dispersal limited.^[98] Flatworms (Turbellaria, Platyhelminthes), such as Pseudobiceros bedfordi, display aggressive hypodermic insemination, where one penetrates the other's body wall to deposit sperm, resolving sexual role conflicts in mobile, low-density environments.^[97] Sequential hermaphroditism also occurs in certain marine invertebrates, adapting to size-dependent fecundity or harem dynamics. The slipper snail Crepidula fornicata (Gastropoda, Mollusca) undergoes protandry, starting as males attached atop stacks of females and transitioning to females upon dislodgement, with sex change triggered by environmental cues like substrate availability; this maximizes lifetime reproduction as larger individuals produce more eggs.^[99] Planktonic groups like chaetognaths and ctenophores are exclusively hermaphroditic, often self-fertilizing in sparse oceanic populations to ensure propagation despite rarity of conspecific encounters.^[100] Some decapod crustaceans, including lysmatid shrimps, show protandrous shifts driven by energetic asymmetries, with initial male phases requiring less investment than egg-bearing females.^[101] In protists, true hermaphroditism—defined as simultaneous production of distinct anisogamous gametes (ova and sperm) within one organism—is uncommon due to their predominantly unicellular or colonial structure and prevalence of isogamy or mating types.^[102] Sexual reproduction instead manifests through syngamy of compatible gametes or conjugation, as in ciliates like Paramecium, where pairs of opposite mating types temporarily fuse to exchange haploid micronuclei, enabling genetic recombination without morphological sex organs; this reciprocal process mirrors cross-fertilization in multicellular hermaphrodites, occurring under stress to restore vigor.^[103]^[104] Parasitic protists such as Plasmodium exhibit gametocytogenesis, differentiating into male (microgametes) and female (macrogametes) forms within hosts, but these arise from separate lineages rather than individual-level hermaphroditism, facilitating outcrossing in vector-mediated cycles.^[105] Such mechanisms prioritize variability over self-compatibility, reflecting protists' ancient eukaryotic origins where sex evolved for DNA repair and adaptation amid environmental flux.^[105]

Hermaphroditism in Humans

True Hermaphroditism (Ovotesticular Disorders of Sex Development)

Ovotesticular disorder of sex development (OT-DSD), formerly known as true hermaphroditism, is defined by the presence of both ovarian and testicular tissue in a single individual, distinguishing it from other disorders of sex development where only one gonadal type develops abnormally.^[106] ^[107] The gonads may consist of one ovary and one testis, two ovotestes, or one ovotestis paired with an ovary or testis, with ovotestes—gonads containing both tissue types—occurring in approximately two-thirds of cases.^[106] This condition arises during embryonic gonadal differentiation, where bipotential gonadal ridges fail to commit fully to either ovarian or testicular pathways, resulting in mixed tissue development rather than sequential or adaptive hermaphroditism seen in some non-human species.^[108] The etiology remains unclear in most cases, but genetic factors predominate, with approximately 60-70% of individuals exhibiting a 46,XX karyotype, often involving translocation of the SRY gene (typically on the Y chromosome) to an X chromosome, which triggers partial testicular differentiation in an otherwise ovarian-primed genome.^[106] ^[109] Other karyotypes include 46,XY (10-20%) or mosaicism/chimerism such as 46,XX/46,XY, where cell lines of both sexes coexist due to post-zygotic errors like nondisjunction or fusion of fraternal twins.^[110] ^[13] Environmental or hormonal influences are hypothesized but lack empirical support as primary causes, and no single mutation accounts for the majority of cases.^[111] OT-DSD has an estimated prevalence of less than 1 in 20,000 live births worldwide, comprising 3-10% of all diagnosed disorders of sex development, though underreporting may occur in regions with limited diagnostic access.^[112] ^[113] Clinically, most cases (about 80%) present at birth with ambiguous external genitalia, such as micropenis, hypospadias, or clitoromegaly, alongside variable internal structures like a uterus or vaginal anomalies; a smaller subset is identified later due to primary amenorrhea or inguinal hernias containing gonadal tissue.^[108] ^[114] Hormonal profiles are inconsistent, with elevated gonadotropins common but variable testosterone or estrogen levels depending on functional tissue proportions.^[115] Diagnosis requires histopathological confirmation via gonadal biopsy, as imaging (ultrasound or MRI) and hormone assays alone cannot reliably distinguish OT-DSD from other conditions like gonadal dysgenesis.^[116] Karyotyping and fluorescence in situ hybridization for SRY detect genetic underpinnings in over 90% of cases, guiding risk assessment for malignancy, as affected gonads carry a 2-5% lifetime risk of tumors like gonadoblastoma, particularly in dysgenetic testicular tissue.^[117] ^[109] Fertility is exceptionally rare, with isolated reports of ovulation and menstruation in 46,XX-dominant cases but no documented self-fertilization or viable offspring from both tissue types simultaneously, underscoring the disorder's developmental pathology over functional duality.^[106] ^[111]

Male and Female Pseudohermaphroditism

Male pseudohermaphroditism refers to a condition in individuals with a 46,XY karyotype and testes, where the external genitalia fail to develop fully masculine characteristics, resulting in ambiguity or feminization due to defects in androgen synthesis, metabolism, or action.^[118] ^[119] Common causes include androgen insensitivity syndrome (AIS), characterized by mutations in the androgen receptor gene leading to partial or complete resistance to androgens; 5α-reductase deficiency, impairing conversion of testosterone to dihydrotestosterone essential for male external genital development; and defects in testosterone biosynthesis enzymes such as 17β-hydroxysteroid dehydrogenase deficiency.^[118] ^[120] These genetic defects are typically autosomal recessive, with AIS prevalence estimated at 1 in 20,000 to 1 in 99,000 male births, while 5α-reductase deficiency occurs in clusters in specific populations, such as 1 in 90 in certain Dominican kindreds.^[121] Affected individuals often present with female-appearing genitalia at birth, undescended testes, and may undergo virilization at puberty in partial forms, though fertility is generally impaired due to absent or dysfunctional spermatogenesis.^[122] Female pseudohermaphroditism describes a condition in 46,XX individuals with ovaries, where excessive androgen exposure during fetal development causes masculinization of the external genitalia, such as clitoromegaly, labial fusion, or urogenital sinus formation, while internal female structures like the uterus remain intact.^[123] The primary cause is congenital adrenal hyperplasia (CAH), particularly 21-hydroxylase deficiency, an autosomal recessive disorder disrupting cortisol synthesis and leading to androgen overproduction; this accounts for over 90% of cases, with classic salt-wasting form incidence at 1 in 15,000 live births and simple virilizing form at 1 in 500 to 1 in 3,000.^[124] Other etiologies include 11β-hydroxylase deficiency or maternal androgen exposure, though rarer.^[125] Unlike male cases, female pseudohermaphroditism often allows for fertility post-treatment, as ovarian function is preserved, but untreated CAH risks life-threatening adrenal crises in infancy.^[126] Both forms fall under disorders of sex development (DSD) with undervirilization in males or virilization in females, diagnosed via karyotyping, hormone assays, and imaging; empirical data from registries show male pseudohermaphroditism comprises about 20-30% of 46,XY DSD cases, rarer overall than female forms driven by CAH.^[127] Causal mechanisms stem from disruptions in the hypothalamic-pituitary-gonadal axis or steroidogenesis pathways, underscoring the binary sex determination process where gonadal identity dictates phenotype unless genetically perturbed.^[128] Prognosis depends on etiology, with glucocorticoid replacement enabling near-normal outcomes in CAH but persistent infertility or gender dysphoria risks in AIS.^[129]

Genetic, Hormonal, and Developmental Causes

True hermaphroditism, or ovotesticular disorder of sex development (DSD), arises primarily from disruptions in the genetic mechanisms governing gonadal differentiation, with the majority of cases featuring a 46,XX karyotype despite the presence of both ovarian and testicular tissue.^[112] In these instances, testicular development in XX individuals often results from translocation of Y-chromosome material, particularly the SRY gene, to an X chromosome or autosome, overriding the default ovarian pathway.^[130] Chimerism, involving the fusion of 46,XX and 46,XY zygotes, or mosaicism such as 46,XX/46,XY karyotypes, accounts for a subset of cases, leading to heterogeneous cell lines that produce dual gonadal tissues.^[131] Monogenic causes include mutations in genes like RSPO1, WNT4, or WT1, which disrupt ovary-determining pathways and permit ectopic testicular differentiation; for example, loss-of-function RSPO1 mutations have been identified in familial 46,XX ovotesticular DSD.^[132] Partial deletions in DMRT1, a gene essential for testis maintenance, have also been linked to 46,XY ovotesticular DSD by impairing proper gonadal commitment.^[131] Male pseudohermaphroditism, characterized by 46,XY karyotype with undervirilized external genitalia, stems from genetic defects impairing androgen action or synthesis during critical developmental windows (weeks 8-12 of gestation). Complete or partial androgen insensitivity syndrome (AIS) results from mutations in the androgen receptor (AR) gene on the X chromosome, rendering tissues unresponsive to testosterone and dihydrotestosterone (DHT), thus failing to masculinize Wolffian ducts or external genitalia.^[122] 5-alpha-reductase type 2 deficiency, caused by SRD5A2 gene mutations, prevents conversion of testosterone to DHT, essential for prostate and external genital virilization, often presenting with female-appearing genitalia at birth that virilize at puberty.^[122] Biosynthetic defects, such as 17-beta-hydroxysteroid dehydrogenase 3 deficiency (SRD5B1 mutations), reduce testosterone production from androstenedione, further contributing to undermasculinization.^[133] Female pseudohermaphroditism, involving 46,XX individuals with virilized genitalia, is predominantly driven by excess androgen exposure prenatally, most commonly from congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (CYP21A2 gene mutations), affecting 1 in 15,000 births and causing cortisol synthesis blockade with shunting to androgen pathways.^[134] This enzymatic defect leads to elevated androstenedione and testosterone from fetal adrenals, promoting clitoromegaly and labial fusion.^[135] Less frequent hormonal etiologies include aromatase deficiency (CYP19A1 mutations), impairing estrogen production and resulting in unopposed maternal or fetal androgens virilizing the genitalia.^[129] Exogenous maternal androgens or androgen-secreting tumors can mimic these effects but are rarer.^[135] Developmentally, these conditions reflect failures in the bipotential gonad's commitment phase, where SRY expression initiates Sertoli cell differentiation and testis formation around week 7; absence or dysregulation defaults to ovarian development via FOXL2 and other factors, but genetic mosaics or hormonal surges can induce mixed or ectopic differentiation.^[136] Müllerian inhibiting substance (AMH) and testosterone subsequently direct internal tract regression and virilization, with insufficiencies yielding persistent Müllerian structures or ambiguous phenotypes; such disruptions underscore the binary sex determination cascade's sensitivity to dosage effects and timing.^[137]

Prevalence, Diagnosis, and Prognosis

Ovotesticular disorder of sex development (OT-DSD), formerly known as true hermaphroditism, has a prevalence of less than 1 in 20,000 live births, making it the rarest form of disorder of sex development (DSD).^[106]^[138] Approximately 500 cases have been documented worldwide as of recent reports.^[139] In contrast, pseudohermaphroditic conditions—such as congenital adrenal hyperplasia leading to female pseudohermaphroditism—are more common, with classic 21-hydroxylase deficiency occurring in about 1 in 15,000 births in white populations.^[124] Overall DSD incidence, encompassing both true and pseudo forms, is estimated at 1 in 5,500 newborns, though OT-DSD constitutes only 3-10% of these cases.^[108] Diagnosis of OT-DSD requires confirmation of both ovarian and testicular tissue, typically via histopathological examination of gonadal biopsies or surgical specimens, as imaging alone may not distinguish ovotestes reliably.^[140] Initial evaluation often begins with karyotyping to identify chromosomal patterns (e.g., 46,XX, 46,XY, or mosaicism), pelvic ultrasound for gonadal assessment, and endocrine testing such as human menopausal gonadotropin stimulation to evaluate gonadal function.^[141]^[142] Ambiguous external genitalia at birth prompts investigation, but some cases present later with primary amenorrhea or virilization; definitive diagnosis hinges on histological proof of ovarian follicles and testicular elements, either in separate gonads or combined ovotestes.^[116] For pseudohermaphroditism, diagnosis focuses on mismatched gonadal and phenotypic sex, often through hormone assays (e.g., elevated androgens in female pseudohermaphroditism) and genetic testing for specific etiologies like androgen insensitivity syndrome.^[118] Prognosis for OT-DSD varies by gonadal functionality and assigned sex, with fertility achieved rarely; functional ovarian tissue may allow menstruation in about 50% of female-assigned cases, but viable pregnancies are exceptional due to immature or dysgenetic testicular components and inbreeding risks from self-fertilization potential, though self-fertilization does not occur in humans.^[143] Individuals with 46,XX karyotype and preserved ovaries have higher fertility prospects than 46,XY cases, which are typically sterile absent a Y chromosome's fertility factors.^[110] Long-term health risks include elevated gonadal malignancy potential, particularly from dysgenetic testicular tissue, necessitating surveillance or prophylactic gonadectomy in some protocols.^[117]^[144] Psychosocial outcomes depend on early multidisciplinary management, though data on adult quality of life remain limited, with many requiring hormone replacement post-gonadectomy.^[145] Pseudohermaphroditic conditions generally carry better fertility prognoses if treated early, such as glucocorticoid therapy for CAH to mitigate virilization and preserve reproductive function.^[124]

Evolution and Functional Ecology

Evolutionary Theories and Models

The low-density model explains the evolution of simultaneous hermaphroditism in lineages where mate encounter rates are low due to sparse populations, sessile lifestyles, or limited dispersal, enabling reciprocal fertilization between any two individuals and thereby increasing reproductive assurance compared to gonochoristic systems reliant on opposite-sex pairing.^[146] This hypothesis, articulated by Ghiselin in 1969, predicts higher mating success for hermaphrodites under such constraints, as evidenced in taxa like barnacles and certain polychaetes where density correlates with hermaphroditic prevalence.^[147] Empirical support includes experimental manipulations showing elevated selfing or bilateral insemination in low-density conditions, though outcrossing remains preferred when possible to mitigate inbreeding depression.^[148] In contrast, the size-advantage hypothesis accounts for sequential hermaphroditism, positing that sex change occurs when an individual's projected reproductive success as the alternative sex exceeds that of its current sex, typically driven by size-dependent fecundity gains that differ between sexes.^[149] Ghiselin's 1969 formulation predicts protogyny (female-to-male change) when male reproductive output scales more steeply with body size, as in many reef fishes where larger males monopolize spawning; phylogenetic tests across labrids confirm this pattern, with hermaphroditism evolving alongside size-fecundity asymmetries.^[150] Protandry (male-to-female) arises oppositely, often in species with early male-biased mortality or female size advantages, though it proves less stable evolutionarily due to vulnerabilities in mate competition.^[151] Sex allocation models extend these frameworks by optimizing resource partitioning between male and female functions in simultaneous hermaphrodites, incorporating factors like local mate competition, sperm limitation, and egg-trading behaviors to predict stable investment ratios.^[152] For instance, in systems with frequent multiple paternity, theory favors reduced male allocation to avoid wasteful sperm overproduction, while delayed reciprocity (tit-for-tat egg exchange) stabilizes mutualism in paired encounters, as modeled for opisthobranchs.^[153] Across kingdoms, gametic or offspring competition further shapes transitions, with hermaphroditism favored when it minimizes rivalry among sibs or pollen tubes, per macroevolutionary analyses of marine and terrestrial clades.^[154] These models collectively highlight density, size, and allocation as causal drivers, though reversals to gonochorism occur under high-density or anisogamy-favoring conditions.^[32]

Advantages: Mate Availability and Self-Fertilization Risks

Hermaphroditism confers reproductive advantages in scenarios of limited mate availability by enabling individuals to adopt either male or female roles during encounters, thereby ensuring compatibility with any conspecific rather than requiring opposite-sex specificity.^[155] This flexibility is especially adaptive in low-density populations, where the probability of locating an opposite-sex partner diminishes, as modeled in evolutionary simulations showing higher fitness gains for hermaphrodites under sparse conditions compared to gonochoristic (separate-sex) strategies.^[156] For instance, in free-spawning marine invertebrates, hermaphroditic forms maintain reproductive output despite reduced encounter rates, avoiding the demographic costs of failed matings that plague dioecious species.^[157] Self-fertilization serves as a fallback mechanism in extreme mate scarcity, providing reproductive assurance by allowing gamete production without external partners, which can elevate transmission rates to near 100% under isolation.^[158] However, this strategy incurs substantial risks from inbreeding depression, manifesting as reduced offspring survival, viability, and competitive ability due to homozygosity of deleterious recessive alleles.^[159] Experimental crosses in hermaphroditic nematodes demonstrate that selfed progeny exhibit fitness declines of up to 50% relative to outcrossed counterparts, with effects compounding across generations absent purging selection.^[160] Consequently, many hermaphroditic lineages evolve outcrossing biases or self-incompatibility systems to minimize selfing, prioritizing genetic diversity despite occasional mate shortages.^[161] In populations where selfing evolves as a response to chronic low density, inbreeding depression may be mitigated over time through selective purging, though empirical data indicate persistent costs that constrain its prevalence.^[159]

Disadvantages: Sexual Conflict and Genetic Costs

In simultaneous hermaphrodites, sexual conflict emerges from divergent evolutionary interests between the male and female reproductive functions within the same individual or between mating partners. The male role often favors rapid, low-investment sperm donation, while the female role requires substantial resource allocation to egg production and potential parental care, leading to asymmetries where individuals prefer acting as sperm donors to avoid costs borne by recipients.^[162] This conflict drives antagonistic behaviors, such as mate choice biases toward the male role or resistance to unwanted insemination.^[163] A prominent example is "penile fencing" in polyclad flatworms of the genus Pseudobiceros, where during mating, opponents wield dagger-like penises to hypodermically inject sperm into the partner's body wall, bypassing female reproductive tracts and attempting unilateral fertilization while evading reciprocal insemination. Such tactics escalate harm, as traumatic insemination can cause tissue damage and increase infection risk, yet persist because benefits to the donor's fitness outweigh individual costs when fertilization success rises.^[164] In sea slugs like Navanax inermis, hypodermic insemination similarly allows donors to evade recipient defenses, intensifying post-copulatory competition over paternity.^[50] Genetic costs of hermaphroditism primarily stem from self-fertilization, which reduces heterozygosity and exposes recessive deleterious alleles, resulting in inbreeding depression manifested as lowered offspring viability, slower growth, and diminished fertility.^[165] Empirical studies in hermaphroditic snails, such as Physa acuta, reveal selfed progeny suffer 20-50% reductions in survival compared to outcrossed counterparts, attributable to homozygous expression of harmful mutations.^[166] Although repeated selfing can purge these alleles over generations, thereby mitigating depression in adapted populations, initial transitions to high selfing rates impose severe fitness penalties, constraining the evolution of obligate selfing.^[167] Resource allocation trade-offs further compound these costs, as hermaphrodites must divide limited energy between spermatogenesis and oogenesis, often yielding suboptimal sex-specific performance relative to gonochoristic (separate-sex) species specialized in one role. Model organisms like the nematode Caenorhabditis elegans demonstrate that selfing hermaphrodites exhibit halved genetic diversity and elevated mutation loads compared to outcrossing males, underscoring long-term disadvantages in variable environments where heterozygote advantage prevails.^[168] These factors contribute to evolutionary pressures favoring outcrossing mechanisms or shifts to dioecy in lineages where genetic costs outweigh selfing benefits.^[148]

Transitions Between Hermaphroditism and Dioecy

Evolutionary transitions from hermaphroditism to dioecy, characterized by the emergence of separate male and female individuals, have occurred repeatedly across taxa, particularly in angiosperms where dioecy is present in approximately 6% of species despite originating from predominantly hermaphroditic ancestors.^[169] These shifts typically involve the stepwise loss of one sexual function in subsets of individuals, often via intermediate states like gynodioecy (coexistence of females and hermaphrodites) or monoecy (separate male and female organs on the same individual).^[170] Gynodioecy is considered the more stable and prevalent pathway to dioecy because it requires nuclear-cytoplasmic interactions favoring female sterility mutations, whereas androdioecy (males and hermaphrodites) is rare due to its genetic instability under most conditions.^[171] In plants, genetic mechanisms driving these transitions include mutations causing male or female sterility, often linked to sex-determining loci that evolve from autosomal genes, with XY systems more common than ZW due to dominance effects at the locus during invasion from hermaphroditism.^[172] For instance, suppression of male fertility in hermaphrodites can lead to female-biased populations, followed by selection for reduced female function in remaining hermaphrodites to establish full dioecy.^[173] Ecological factors, such as pollination efficiency and inbreeding avoidance, facilitate these changes, with models showing that pollen limitation or spatial separation favors specialization into unisexual roles.^[174] Reversals from dioecy to hermaphroditism are less frequent but documented, often through the restoration of lost sexual functions under high selfing costs or population bottlenecks, as demonstrated in experimental evolution with the dioecious alga Volvox carteri where hermaphroditism re-emerged within generations.^[175] Among animals, transitions are less common and predominantly from hermaphroditism to dioecy in lineages shifting toward mobility, such as from sessile invertebrates to mobile vertebrates, though reversals occur in confined environments like parasites or island populations.^[176] In fish, for example, sequential hermaphroditism in species like wrasses can represent a labile state facilitating shifts to gonochorism (dioecy), driven by size- or density-dependent selection where sex allocation models predict unisex specialization when mating groups are small.^[177] Genetic underpinnings mirror plants, involving sterility mutations, but animal transitions often correlate with chromosomal sex determination evolving post-separation of functions, with evidence from mollusks showing dioecy invading hermaphroditic clades via Y-chromosome suppression of female traits.^[176] Overall, while forward transitions predominate due to advantages in resource allocation and reduced inbreeding, the lability of sexual systems underscores their responsiveness to demographic and environmental pressures.^[178]

Controversies and Debates

Medical Management and Surgical Interventions

Medical management of ovotesticular disorders of sex development (OT-DSD), formerly termed true hermaphroditism, typically involves a multidisciplinary approach including endocrinologists, surgeons, geneticists, and mental health professionals to assess gonadal function, hormonal status, and potential fertility preservation. Hormone therapy, such as estrogen or testosterone replacement, is often required following gonadectomy to support pubertal development and prevent complications like osteoporosis.^[106]^[179] Diagnosis relies on karyotyping, imaging, and biopsy to identify ovotestes, guiding decisions on sex assignment, which favors the more viable gonad (often ovarian tissue in 46,XX cases).^[180] Surgical interventions historically emphasized early genital reconstruction to align external appearance with assigned sex, including clitoroplasty, vaginoplasty, or phalloplasty, performed in infancy to reduce parental distress and facilitate rearing. However, such procedures frequently result in complications like scarring, urinary incontinence, diminished sexual sensation, and need for revisions, with long-term studies showing no proven improvement in psychosocial outcomes.^[181]^[182] Gonadectomy targets non-functional or malignant-risk tissue, but conservative approaches preserve concordant gonads to maintain fertility potential, as seen in follow-ups of 33 cases where no gender changes occurred post-surgery.^[183]^[184] Contemporary guidelines, influenced by evidence of harm from irreversible early interventions, advocate deferring non-essential surgeries—such as cosmetic genitoplasty—until adolescence or adulthood to allow patient consent and self-determination.^[185]^[186] The Pediatric Endocrine Society and similar bodies recommend surgery only for urgent medical needs, like obstruction or high malignancy risk (e.g., 46,XY ovotestes), prioritizing functional outcomes over aesthetics.^[187]^[188] Outcomes data from cohorts indicate higher regret and dissatisfaction with childhood surgeries, including loss of orgasmic function in up to 40% of cases, underscoring the ethical concerns over performing procedures without robust evidence of net benefit.^[189]^[190] Debates persist on timing, with some clinicians arguing for interventions between 6-18 months in select cases (e.g., severe virilization) to optimize technical success, yet systematic reviews highlight insufficient randomized data and potential overtreatment driven by historical norms rather than patient-centered evidence.^[187]^[191] In OT-DSD specifically, where malignancy risk in ovotestes is low (under 5% in followed series), ongoing surveillance via biopsy at puberty is preferred over prophylactic removal, reflecting a paradigm shift toward minimizing iatrogenic harm.^[192]^[144]

Terminology Shifts and Intersex Activism

In the late 20th century, medical terminology for humans with atypical sexual development shifted from "hermaphrodite" and its subtypes—true hermaphroditism (presence of both ovarian and testicular tissue) and pseudohermaphroditism (discordance between internal gonads and external genitalia)—to "intersex," largely influenced by patient advocacy groups. This change gained momentum in the 1990s, as activists argued that "hermaphrodite" evoked mythological figures with fully functional dual sexes, a rarity in humans where most cases involve non-functional or underdeveloped tissues, thereby stigmatizing individuals and implying a false equivalence to animal hermaphroditism. The term "intersex" was proposed earlier in medical literature, with British physician A. P. Cawadias suggesting it in 1943 to describe conditions intermediate between male and female, but its widespread adoption in advocacy contexts emphasized variation over pathology.^[193]^[194] Central to this terminological evolution was the Intersex Society of North America (ISNA), founded in 1993 by activist Cheryl Chase (also known as Bo Laurent), who, following her own experience with clitoroplasty as an infant, publicized personal testimonies and critiqued medical secrecy and interventions in outlets like The Sciences magazine. ISNA advocated "intersex" to foster community identity, align with broader LGBTQ+ movements, and challenge the medical model's focus on "normalizing" surgeries performed without patient consent, often in infancy, which activists claimed caused psychological trauma and loss of sensation. By the early 2000s, ISNA and affiliates influenced guidelines, such as a 2005 proposal co-authored by Chase and bioethicist Alice Dreger, to retire pseudohermaphroditism labels for being scientifically imprecise and pejorative, prioritizing patient-centered language over taxonomic accuracy. However, ISNA's advocacy, rooted in personal narratives and queer theory influences, has been critiqued for downplaying empirical evidence of associated health risks like infertility, gonadal cancer, and hormonal imbalances in these conditions.^[195]^[196]^[197] The activist-driven preference for "intersex" faced pushback from clinicians, culminating in the 2006 Chicago Consensus Conference, where pediatric endocrinologists adopted "disorders of sex development" (DSD) to underscore the developmental anomalies' medical implications, including higher morbidity rates—such as a 5-20% risk of gonadal malignancy in certain karyotypes—rather than framing them as neutral identities. Activists, including successors to ISNA (which disbanded in 2008), rejected DSD as pathologizing innate traits, arguing it reinforced binary sex norms and ignored self-reported quality-of-life data favoring delayed interventions; yet surveys indicate parental confusion with "intersex," which often evokes gender fluidity over biological discordance, potentially hindering informed consent. This debate highlights tensions between activist narratives, which prioritize destigmatization and draw from ideologically aligned sources like transgender advocacy, and causal evidence from genetics and endocrinology showing these traits as errors in dimorphic sex differentiation rather than adaptive variations. Multiple studies post-2006 report persistent terminology discord, with "intersex" retaining cultural salience in media despite limited clinical use.^[198]^[199]^[200]^[197]

Implications for Biological Sex Binary and Human Dimorphism

Ovotesticular disorders of sex development (DSD), formerly termed true hermaphroditism, involve the presence of both ovarian and testicular tissue in an individual, occurring in approximately 1 in 100,000 live births and representing less than 10% of all DSD cases.^[201] ^[15] These conditions arise from genetic, hormonal, or developmental anomalies during embryogenesis, often with a 46,XX karyotype, but affected individuals rarely achieve functional fertility in both reproductive roles and typically exhibit infertility overall due to immature or non-viable gametes.^[106] ^[110] Biologically, human sex is binary, determined by anisogamy—the dimorphic production of either small, motile sperm or large, immotile ova—with no third gamete type observed in mammals, rendering ovotesticular DSDs as pathological deviations rather than evidence of a spectrum or intermediate sex.^[202] ^[203] Such DSDs do not erode the sex binary, as they constitute disorders of sexual differentiation affecting fewer than 0.02% of births, with the vast majority of humans (over 99.98%) exhibiting unambiguous male or female traits aligned with gamete production potential.^[203] In ovotesticular cases, gonadal tissues coexist but do not enable simultaneous or balanced reproduction as in non-mammalian hermaphrodites; instead, one tissue type often predominates, and individuals are medically assigned to male or female categories based on predominant anatomy, chromosomes, or function.^[202] This aligns with causal mechanisms of sex determination, where the SRY gene on the Y chromosome typically initiates male development, and its absence or mosaicism leads to mixed outcomes without creating viable alternatives to the binary framework.^[204] Human sexual dimorphism—evident in average differences such as greater male height (about 10% taller globally), upper-body strength (50-60% greater), and reproductive anatomy—operates at the species level, with DSDs representing rare exceptions that reinforce rather than challenge the bimodal distribution of traits.^[203] Population-level data show sex-linked characteristics clustering into two distinct modes, with intersex anomalies falling as outliers within male or female ranges or as non-reproductive pathologies, not bridging categories.^[202] Empirical studies confirm that even in DSDs, no individuals produce both functional sperm and ova, preserving the reproductive basis of dimorphism.^[106] Debates arise from interpretations claiming DSDs demonstrate sex as a continuum, often advanced by intersex advocacy groups to critique binary norms, but these overlook that such conditions are congenital anomalies akin to other developmental disorders (e.g., congenital adrenal hyperplasia), not normative variations.^[202] Critiques, such as those from biologist Emma Hilton and mathematician Colin Wright, argue that aggregating DSDs inflates prevalence to imply commonality, whereas disaggregating reveals most as non-ambiguous (e.g., Klinefelter syndrome as male variants), with true ovotesticular ambiguity affecting 1 in tens of thousands.^[202] This perspective prioritizes reproductive biology over superficial trait mosaicism, maintaining that human dimorphism evolved for gamete-specific roles, unaffected by pathological rarities.^[203]

References

[1]
Hermaphrodite - Definition and Examples - Biology Online Dictionary
Jan 5, 2024 · Hermaphrodites are living organisms who are either born with or can possess both male and female reproductive organs at some point in their ...Hermaphrodite Definition · Zoology · Botany · Use Regarding Humans
[2]
Hermaphrodite - Etymology, Origin & Meaning
Originating in late 14th-century from Latin hermaphroditus and Greek hermaphroditos, the word means a person with both male and female attributes.
[3]
Hermaphroditism: What's not to like? - PubMed
Hermaphroditism is rare and phylogenically in decline among animal species. The evolutionary basis for this development is not well understood.
[4]
True Hermaphroditism and Mixed Gonadal Dysgenesis in Young ...
Oct 1, 2002 · True hermaphroditism (TH) refers to individuals who have both unequivocal ovarian tissue and testicular elements regardless of their ...
[5]
clinical features, genetic variants and gonadal histology - PubMed
True hermaphroditism is a rare cause of intersexuality in which both ovarian and testicular tissue is present in the same individual.
[6]
True hermaphroditism: a clinical description and a ... - PubMed
True hermaphroditism is a very rare form of ambiguous genitalia characterized by the presence of both ovarian and testicular tissue in the same individual.
[7]
True hermaphroditism: geographical distribution, clinical ... - PubMed
We reviewed 283 cases of human true hermaphroditism published from 1980 to 1992. Of the 96 cases described in Africa 96.9% showed a 46,XX karyotype.
[8]
HERMAPHRODITUS (Hermaphroditos) - Theoi Greek Mythology
The name is compounded of Hermes and Aphrodite, and is synonymous with androgunês, gunandros, hêmiandros, &c. He was originally a male Aphrodite (Aphroditus), ...
[9]
HERMAPHRODITE Definition & Meaning - Merriam-Webster
1. an animal or plant having both male and female reproductive organs, structures, or tissue : an organism exhibiting hermaphroditism
[10]
Ancient Rome and Intersex People, Those Known to the Romans as ...
Oct 3, 2015 · As such, intersex people could be considered as punishments or warnings from the gods. – The Romans coined the term hermaphrodite, after ...
[11]
How the Renaissance Idea of Hermaphrodites Helped Drive the ...
Mar 26, 2018 · Throughout the early part of the 17th century, people classified as “hermaphrodites” continued to be allowed to choose a gender expression and ...
[12]
[PDF] Rationalizing Sex: the Hermaphrodite in Eighteenth Century Medical ...
In eighteenth-century Europe, medical writers rejected the existence of human hermaphrodites as contrary to reason. This paper examines the underlying logic ...<|control11|><|separator|>
[13]
We used to call them hermaphrodites | Genetics in Medicine - Nature
True hermaphrodites have both testicular and ovarian tissue. As noted by Dreger, this model, centered on the gonadal anatomy, was adopted by clinicians, and all ...
[14]
Hermaphrodite | Definition, Reproduction & Examples - Lesson
A hermaphrodite is a creature that has both male and female reproductive organs, representing a small percentage of animals and plants.
[15]
True Hermaphrodite: A Case Report - PMC - PubMed Central
The causes of true hermaphroditism remain enigmatic and the commonest presentation is an abnormal external genitalia ranging from normal male to normal female.
[16]
HERMAPHRODITE Definition & Meaning | Dictionary.com
Biology., an organism, such as an earthworm or plant, having both male and female reproductive organs at the same time or throughout the lifespan.
[17]
Hermaphroditism - an overview | ScienceDirect Topics
Hermaphroditism is defined as a rare condition where both ovarian and testicular tissues coexist in the same individual, often accompanied by chromosomal male- ...<|separator|>
[18]
Hermaphrodites - BYJU'S
An organism possessing both male and female organs is called hermaphrodite. Males in sexually reproducing species have organs that create male gametes, often ...
[19]
8.10 Understanding Hermaphroditism – The Evolution and Biology ...
You can probably imagine a few benefits of hermaphroditism (having the ability to produce both eggs and sperm). For one, any individual could mate with any ...
[20]
What Is Intersex, Intersex Surgery - Cleveland Clinic
Jul 19, 2022 · Is a person who is intersex a hermaphrodite? No. Hermaphrodites don't exist. That is an outdated term implying that a person is both fully ...
[21]
True Hermaphroditism - an overview | ScienceDirect Topics
True hermaphroditism, a rare and usually sporadic disorder, is defined as the coexistence of seminiferous tubules and ovarian follicles.
[22]
Consequences of sex change for effective population size - PMC - NIH
Sequential hermaphroditism, a reproductive strategy in which individuals operate first as males and later as females (protandry) or the reverse (protogyny), is ...
[23]
Sequential Hermaphroditism - an overview | ScienceDirect Topics
There are six major sexual systems that involve hermaphroditism: simultaneous hermaphroditism with obligate selfing; simultaneous hermaphroditism with ...
[24]
Simultaneous Hermaphroditism - an overview | ScienceDirect Topics
Simultaneous hermaphroditism is when an individual produces sperm and ova at the same time, allowing for self or cross-fertilization.
[25]
Pseudohermaphroditism - an overview | ScienceDirect Topics
Pseudohermaphroditism is when external genitalia don't match gonadal sex, with one type of gonadal tissue but the opposite phenotype.
[26]
Pseudohermaphroditism - an overview | ScienceDirect Topics
Pseudohermaphroditism refers to a mismatch between gonadal sex and phenotypic sex, e.g. a female hermaphrodite will have ovaries but masculinized genitalia.
[27]
Gonochorism - an overview | ScienceDirect Topics
Gonochorism is defined as a reproductive strategy in which individuals of a species possess one of at least two distinct sexes.
[28]
Gonochorism vs. hermaphroditism: relationship between life history ...
Jan 17, 2006 · The gonochoristic and hermaphroditic species differ in all the main life-history parameters and also in demographic characteristics.
[29]
[PDF] Gonochorism - Todd Shackelford
Gonochorism is the condition of individual organ- isms within a species existing as one of two pos- sible sexes, specifically male or female. Gonochorism ...Missing: plants | Show results with:plants
[30]
Switches, stability and reversals in the evolutionary history of sexual ...
While all hermaphroditic forms revert quickly to gonochorism, protogyny and simultaneous hermaphroditism are evolutionarily more stable than protandry.
[31]
a test in a hermaphroditic and a gonochoric congeneric species of ...
Hermaphroditism and gonochorism are two contrasting forms of sexuality. Hermaphroditic species are generally seen as species adapted to conditions of low ...
[32]
A reconstruction of sexual modes throughout animal evolution
Dec 6, 2017 · We coded all sexually reproducing taxa as either simultaneous hermaphrodites or gonochoristic, but many animal species have more complicated ...<|separator|>
[33]
A reconstruction of sexual modes throughout animal evolution - PMC
Dec 6, 2017 · Many transitions between hermaphroditism and gonochorism in both plants and animals almost certainly involve intermediate reproductive states ( ...Ancestral State... · Discussion · Associated DataMissing: definition | Show results with:definition<|separator|>
[34]
Hermaphroditism and gonochorism. a new hypothesis on the ...
Most crustaceans are gonochoristic but hermaphroditism occurs in primitive classes as well as in different orders of higher Crustacea.
[35]
Sequential Hermaphroditism - an overview | ScienceDirect Topics
Sequential hermaphroditism is defined as a sexual system in which an individual organism produces both male and female gametes at different periods of its ...
[36]
Sequential Hermaphroditism - an overview | ScienceDirect Topics
The SAM posits that sex change is adaptive when the reproductive value is greater as one sex when small and the other sex when larger (older).
[37]
Ecological and evolutionary consequences of alternative sex ...
Aug 22, 2017 · Fish change sex from male to female (protandry) or vice versa (protogyny). Protandry has near-random mating, while protogyny has aggregate/ ...
[38]
Sex change in sequentially hermaphroditic slipper limpets
Oct 24, 2019 · Slipper limpets change sex from male to female as they grow. This is thought to be a way to increase the reproductive output of these sedentary, filter-feeding ...
[39]
Does the Presence of Boring Sponges Alter Timing of Sex Change ...
AbstractThe Atlantic slipper limpet, Crepidula fornicata, is a sequential hermaphrodite whose size at sex change is plastic with respect to social and ...
[40]
Sex change in clownfish - The Australian Museum
The process in which a male turns into a female later in its life is known as protandrous sequential hermaphroditism, or protandry. Clownfish are part of the ...Missing: mechanism | Show results with:mechanism
[41]
Sex Change in Clownfish: Molecular Insights from Transcriptome ...
Oct 17, 2016 · The male is poised to become female and rapidly changes sex to assume the vacated position, while the largest undifferentiated fish completes ...
[42]
Five fascinating facts about parrotfish - Great Barrier Reef Foundation
Apr 28, 2021 · Parrotfish are gender fluid colour changers. Parrotfish change their sex throughout their lives, swapping from female to male as they grow.
[43]
Hormonal control of sex and color change in the stoplight parrotfish ...
The stoplight parrotfish, Sparisoma viride, changes sex from female to male. In most cases, sex change is accompanied by dramatic change in coloration.
[44]
Leveraging sex change in parrotfish to manage fished populations
Oct 8, 2018 · The life history of parrotfish complicates management decisions because they transition from a mostly female “initial phase” to an all-male “ ...
[45]
The Adaptive Significance of Sequential Hermaphroditism in Animals
In some cases, sequential hermaphroditism can convey a selective advantage to an individual, by increasing its reproductive potential relative to ...
[46]
A phylogenetic comparative analysis on the evolution of sequential ...
Feb 27, 2020 · We show that protogyny and protandry evolve from gonochorism but evolutionary transitions between these two forms of sequential hermaphroditism are unlikely to ...
[47]
https://answersingenesis.org/animals/hermaphroditism-in-animals/
[48]
(PDF) Strategic mating effort in a simultaneous hermaphrodite
Aug 7, 2025 · We studied the mating behavior of the simultaneously hermaphroditic flatworm Macrostomum lignano and tested for a strategic mating effort in ...
[49]
Sexual selection and reproductive success in hermaphroditic ...
In the 7 species where data exist, there is a significant increase in male reproductive success with individual size, and in all but 1 species success through ...
[50]
[PDF] Sexual selection in a simultaneous hermaphrodite with hypodermic ...
This study investigated the effect of body size on mating patterns, egg production (an indirect measure of sperm transfer) and paternity in Alderia modesta, a ...
[51]
Understanding Speciation in fish called “hamlets” | Smithsonian ...
Mar 13, 2017 · However, hamlets are simultaneous hermaphrodites, meaning they are both male and female at the same time. This is quite rare among fish (and ...<|separator|>
[52]
Mate-search efficiency can determine the evolution of ... - PubMed
When low population density or low mobility of a species limits the number of potential mates, simultaneous hermaphrodites may have a selective advantage ...
[53]
Environmental Cues and Mechanisms Underpinning Sex Change in ...
Jun 10, 2021 · In monogamous Red Sea clownfish, for instance, disappearance of the dominant female triggers sex change only if a smaller conspecific is present ...
[54]
The Adaptive Significance of Sequential Hermaphroditism in Animals
Sequential hermaphroditism can convey a selective advantage to an individual by increasing its reproductive potential relative to nontransforming members of ...
[55]
A phylogenetic comparative analysis on the evolution of sequential ...
Feb 27, 2020 · According to the size-advantage model (SAM), selection should favour sex change when the second sex achieves greater reproductive success at a ...
[56]
Patterns of male reproductive success in Crepidula fornicata provide ...
The size-advantage model and sex-allocation theory are frequently invoked to explain the evolution and maintenance of sequential hermaphroditism in many taxa.
[57]
Multiple mating increases cocoon hatching success in the ...
However, we found that multiple mating showed benefits for female reproduction that increased the hatching success of the cocoons. This effect may be a result ...Missing: advantages | Show results with:advantages
[58]
Sexual selection in earthworms: Mate choice, sperm competition ...
Consequently, earthworms constitute an excellent model for studying sexual selection in simultaneous hermaphrodites. Interestingly, these results are more ...
[59]
Monoecy - an overview | ScienceDirect Topics
Monoecy refers to plants with both male and female reproductive structures on the same individual, producing both types of flowers.
[60]
The distribution of sexual function in the flowering plant - Journals
Mar 21, 2022 · Monoecy in plants refers to a separation of sexes across the organism, specifically to the production of unisexual flowers that are spatially ( ...
[61]
The distribution of sexual function in the flowering plant - NIH
Mar 21, 2022 · Considering how common monoecy is, at a frequency 'slightly higher' than the frequency of dioecy, and perhaps as high as 7% of angiosperm ...Missing: prevalence | Show results with:prevalence
[62]
Monoecious vs. Dioecious Plants: Differences and Examples
May 13, 2024 · Dioecious plants have either male or female parts, while monoecious plants have both male and female flowers on the same plant.Monoecious vs. Dioecious Plants · Differences Between... · Unisexual Flowers vs...
[63]
Monoecious, dioecious and hermaphoriditic plants - Plantura Magazin
This is meant to signify that the male and female are in the same house. So, monoecy simply means that the flowers of both sexes are on the same plant.What are monoecious plants? · Planting tips · What are hermaphroditic plants?
[64]
What adaptations have evolved in plants that help monoecious ...
Nov 20, 2023 · An example of a monoecious plant is corn, which has both male tassels and female ears. Corn's flowers mature at different times, and it is ...<|separator|>
[65]
The relative and absolute frequencies of angiosperm sexual systems
Oct 1, 2014 · Also, 1.4% of all angiosperm genera contain dioecious and monoecious species, while 0.4% contain dioecious and gynodioecious species. All ...
[66]
https://www.gardenninja.co.uk/dioecious-vs-monoecious-plants-understanding-the-differences/
[67]
Flower dimorphism and the maintenance of andromonoecy in ...
Jan 24, 2003 · Andromonoecy is a breeding system in which individual plants produce both staminate (male) and perfect (hermaphrodite) flowers. It exists in ...Missing: definition | Show results with:definition
[68]
Superior male function in male flowers of the endangered Sagittaria ...
In addition, offspring fitness provides new insights into the maintenance and evolutionary advantages of andromonoecy, which might otherwise be overlooked.
[69]
The Andromonoecious Sex Determination Gene Predates the ... - NIH
May 12, 2016 · Sex determination is a developmental evolutionary process that leads to unisexual flowers in 10% of the species [1]. Monoecious species (5–6%) ...
[70]
Reproductive biology of the andromonoecious Cucumis melo subsp ...
Aug 11, 2009 · Most cultivars of muskmelons (Cucumis melo) are andromonoecious whereas cucumbers (Cucumis sativus) are normally monoecious (McGregor, 1976). In ...
[71]
Male flowers are better fathers than hermaphroditic flowers in ...
Nov 28, 2011 · Passiflora incarnata is functionally andromonoecious throughout its range with both male morph and hermaphroditic flowers on the same plant ( ...
[72]
Mating consequences of contrasting hermaphroditic plant sexual ...
Aug 10, 2018 · Andromonoecy in this species enables efficient, size-dependent resource allocation, emphasizing female function in large plants.
[73]
The Mendelian inheritance of gynomonoecy
Jan 5, 2020 · Gynomonoecy is an infrequent sexual system in angiosperms, although widely represented within the Asteraceae family. Currently, the hypothesis ...
[74]
Adaptive advantages of gynomonoecious species - ResearchGate
Aug 10, 2025 · Gynomonoecious species have a diversity of floral traits and pollination systems despite that they account for only about 3% of the total ...
[75]
Gynomonoecy in angiosperms: phylogeny, sex expression and ...
Gynomonoecy is the mode of sex expression in which female and bisexual flowers occur on the same plants; it is an important step in the evolution of monoecy ...Missing: definition examples<|separator|>
[76]
gynomonoecious herb through deployment of female and male ...
For example, around 3% of the indi- viduals of Silene noctiflora from field populations were gynomon- oecious, whereas up to 90% were gynomonoecious under.<|control11|><|separator|>
[77]
Gynomonoecy in a mycoheterotrophic orchid Eulophia zollingeri ...
Oct 27, 2020 · Such a sexual system, in which plants have both female and hermaphroditic flowers co-occurring within the same plants, is called gynomonoecy.
[78]
Effect of Hermaphrodite–Gynomonoecious Sexual System ... - MDPI
Apr 1, 2022 · The advantage of the offspring of pistillate (vs. hermaphrodite) flowers may contribute to the maintenance of gynomonoecy in E. anisopterus in ...
[79]
Correlated evolution of fruit size and sexual expression in ...
Oct 1, 2007 · Andromonoecy is hypothesized to evolve as a mechanism enabling plants to independently allocate resources to female and male function.
[80]
Hermaphroditic sex allocation evolves with developmental trade ...
Mar 23, 2025 · Generally speaking, hermaphroditism is regarded as the ancestral sexual system of angiosperms ... Evolution of sexual systems in flowering plants.
[81]
Macroevolutionary synthesis of flowering plant sexual systems
Flowering plants exhibit an unparalleled variety of sexual systems, from combined male and female function within a single flower (hermaphroditism) to entirely ...
[82]
Evolution of Dioecy in Flowering Plants - jstor
Dioecy may evolve directly from hermaphro- ditism or via gynodioecy, androdioecy, and monoecy. In some cases dioecy has evolved from heterostyly.<|separator|>
[83]
The evolution of plant reproductive systems: how often are ... - NIH
Flowering plants are characterized by striking variation in reproductive systems, and the evolutionary lability of their sexual traits is often considered a ...
[84]
Global distribution and evolutionary transitions of angiosperm ...
Jun 14, 2021 · Frequencies of dioecy and monoecy increase with latitude, while hermaphrodites are more frequent in warm and arid regions.<|separator|>
[85]
Global distribution and evolutionary transitions of angiosperm ...
Jun 14, 2021 · Transitions between hermaphroditism and dioecy increased, while transitions to monoecy decreased with paleo-temperature when paleo-temperature > ...
[86]
Spatial Patterns and Drivers of Angiosperm Sexual Systems in ...
Aug 10, 2020 · Similarly, the proportion of woody monoecious species was also positively correlated with mean genus age. These results partly support and ...
[87]
Polyploidy and sexual system in angiosperms: Is there an association?
Jun 27, 2016 · Flowering plants display a variety of sexual systems, ranging from complete cosexuality (hermaphroditism) to separate-sexed individuals ...
[88]
Fungal sexual reproduction and mating-type loci - ScienceDirect.com
Jun 9, 2025 · Unlike animals and plants, fungi do not have conventional male and female sexes but instead rely on mating types, which are determined by ...
[89]
Homothallism: an umbrella term for describing diverse sexual ...
Homothallism in fungi has historically been defined as the ability of a single spore to produce a sexually reproducing colony when propagated in complete ...
[90]
Mating-System Evolution: All Roads Lead to Selfing - ScienceDirect
Aug 5, 2019 · Homothallic fungi are self-fertile: they can sexually reproduce in a culture derived from a single spore or cell. Heterothallic fungi are self- ...
[91]
Obligate sexual reproduction of a homothallic fungus closely related ...
Jun 17, 2022 · Homothallism has evolved multiple times throughout the fungal kingdom, suggesting it confers advantage when population numbers are low or mates ...
[92]
Tetrapolar fungal mating types: Sexes by the thousands
Basidiomycetous fungi display thousands of different mating types that are determined by two genetically unlinked loci.
[93]
Homothallism: an umbrella term for describing diverse sexual ...
Jun 19, 2015 · In fungi, this condition is known as homothallism and ensures that a single individual is able to undergo sexual reproduction, even when a ...
[94]
Transition from heterothallism to homothallism is hypothesised to ...
Whether a species is homo- or heterothallic is determined genetically at the mating type locus (MAT locus) where the presence or absence of two genes, alpha-box ...
[95]
Female Fertility and Mating Type Effects on Effective Population Size ...
The idealized individual in many fungal species is a haploid self-sterile hermaphrodite that may be propagated by asexually produced spores or that may ...
[96]
Simultaneous hermaphroditism – EEBlog
Nov 20, 2020 · These characteristics are found in plants and animals that produce both eggs (or seeds) and sperm (or pollen) at the same time (simultaneously!).
[97]
Precocious Sperm Exchange in the Simultaneously Hermaphroditic ...
Most nudibranch molluscs are thought to be simultaneous hermaphrodites, but detailed studies of reproductive development and timing remain rare as most species ...
[98]
Freshwater Pulmonate (Mollusca: Gastropoda) Reproduction
Being hermaphroditic means an individual freshwater pulmonate is able to produce both eggs and sperm, as part of a diploid adult lifecycle. Spermatogenesis and ...
[99]
Gender-bending fish - Understanding Evolution - UC Berkeley
A hermaphrodite is an organism that has both male and female reproductive organs and can perform both the male and female parts of reproduction.
[100]
Macroevolutionary patterns in marine hermaphroditism - PMC - NIH
For example, some groups of planktonic invertebrates including chaetognaths, ctenophores, and larvaceans are exclusively hermaphroditic (Krumbach 1927; Pianka; ...
[101]
Ray Bauer research: hermaphroditism and sex change
In shrimps, the direction of hermaphroditism can be explained by the energetic difference between eggs and sperm. Egg cells must contain much more energy and ...
[102]
What do isogamous organisms teach us about sex and the two sexes?
Oct 19, 2016 · The two sexes can coexist in one individual, as in simultaneous hermaphrodites (or male and female 'functions'; [17,18]). Most unicellular ...<|separator|>
[103]
23.3: Groups of Protists - Biology LibreTexts
Apr 9, 2022 · The majority view at present is to order all eukaryotes into six supergroups: Excavata, Chromalveolata, Rhizaria, Archaeplastida, Amoebozoa, and Opisthokonta.Missing: hermaphroditism | Show results with:hermaphroditism
[104]
Sexual reproduction and genetic exchange in parasitic protists - PMC
Here, we review some recent studies of sex and genetic exchange in parasitic protists and consider how the various reproductive modes of unicellular parasites ...
[105]
Sex in protists: A new perspective on the reproduction mechanisms ...
This scientific evidence suggests the existence of sex in eukaryotic cells since ancient times, having protists, the most primitive eukaryotes, as the earliest ...
[106]
Ovotesticular Disorder of Sex Development
The exact cause of ovotesticular DSD is known only in a small percentage of patients. Most affected individuals have a 46, XX chromosomal make-up (karyotype), ...Missing: prevalence | Show results with:prevalence
[107]
Ovotesticular DSD (Hermaphroditism)
Ovotesticular DSD (obsolete term: true hermaphroditism) is a disorder of sex development characterized by the presence of both testicular and ovarian tissue.
[108]
Ovotesticular Disorder of Sex Development: Approach and ... - NIH
Oct 5, 2021 · OT-DSD is an uncommon condition with unclear causes. Once a DSD ... The global reported incidence of all DSD conditions is 1/5,500 newborns [3].Missing: definition prevalence
[109]
Gonadoblastoma and Papillary Tubal Hyperplasia in Ovotesticular ...
On the other hand, SRY is present in only 10% of ovotesticular DSD cases with a 46,XX karyotype (3,4,5,6). The testes or testicular components of the ovotestes ...
[110]
Ovotesticular Difference of Sex Development: Genetic Background ...
Overall, ovotesticular DSD is a rare form of DSD, with an estimated incidence of <1/20,000 individuals, representing <5% of all DSD cases, although it appears ...Missing: definition prevalence
[111]
Ovotesticular Disorder of Sex Development: An Unusual Presentation
Jul 12, 2019 · Its prevalence has been reported to be less than 1/20,000, and about 500 affected individuals have been reported to date.Missing: definition | Show results with:definition
[112]
46,XX ovotesticular difference of sex development - Orphanet
Estimated prevalence is approximately 1/20,000 births. The disorder may account for less than 3-10% of all DSD. Clinical description. About 20% of affected ...
[113]
Ovotesticular Disorder of Sex Development Presenting as a Scrotal ...
Nov 22, 2023 · Ovotesticular disease of sex development is a rare disorder with varying karyotypes, accounting for nearly 3% to 10% of all DSD cases. ... The ...
[114]
True hermaphroditism: A nightmare for an adult - LWW
True hermaphrodites have both testicular and ovarian tissues. The patient may present with one ovary and one testis, or more commonly, one or two ovotestes.
[115]
True hermaphroditism: genetic variants and clinical management
The diagnosis and management of 22 patients with true hermaphroditism are described. Sixteen of them were first seen before the age of 4 months.
[116]
True hermaphroditism: diagnosis and surgical treatment - PubMed
We documented a new case of 46,XY true hermaphroditism in an 18-year-old patient, reared as a female at birth, with ambiguous genitalia and primary amenorrhea.
[117]
Ovotesticular Disorders of sexual development (DSD): A rare case of ...
The incidence is 1 in 5,000 live births. Patients with DSD may be at increased risk for developing gonadal and reproductive tract tumors. This report summarizes ...
[118]
Male pseudohermaphroditism: A case study of 46,XY disorder of ...
Sep 10, 2020 · Androgen resistance is one of the most common causes of 46,XY DSD; it is manifested as AIS and classified based on clinical phenotypes into ...
[119]
Male Pseudohermaphroditism - an overview | ScienceDirect Topics
Pseudohermaphroditism is a disorder of phenotypic sex in which patients have normal male or female gonads but ambiguous external genitalia. Male ...
[120]
Volume 5, Chapter 80. Male Pseudohermaphroditism Due to ...
Male pseudohermaphrodites are persons with a Y-chromosome whose external genitalia fail to develop as expected for normal males. Causes of male ...<|separator|>
[121]
Management of neonates and children with male ...
Causes included (1) inadequate testosterone production, (2) incomplete conversion of testosterone to dihydrotestosterone, and (3) insufficient androgen-binding ...
[122]
Male Pseudohermaphroditism Due to Androgen Insensitivity or 5α ...
Causes of male pseudohermaphroditism include cytogenetic abnormalities, teratogenic causes, defects in testosterone biosynthesis, and defects in androgen action ...Missing: definition | Show results with:definition
[123]
Female Pseudohermaphroditism - an overview | ScienceDirect Topics
Female pseudohermaphroditism is defined as a condition resulting from the virilization of a genetically female fetus due to excessive androgen levels, leading ...
[124]
Congenital Adrenal Hyperplasia: Female Pseudohermaphroditism ...
Therefore, female pseudohermaphroditism is a condition in which the gonadal sex is female, but the external genitalia are masculinized. Ambiguous female ...
[125]
Pseudohermaphroditism, Female - SpringerLink
Female pseudohermaphroditism is mainly caused by syndromes of congenital adrenal hyperplasia. Adrenal enzyme defects – 21-hydroxylase deficiency (P450c21), ...
[126]
Female pseudohermaphroditism - Eurorad
Feb 9, 2011 · The causes of female pseudohermaphroditism include congenital adrenal hyperplasia (CAH) and transplacental androgen exposure, being CAH the ...
[127]
Ambiguous Genitalia and Disorders of Sexual Differentiation - NCBI
Aug 28, 2023 · The incidence of a child with a disorder of sexual development (DSD) is approximately 1 in 1000 to 4500 live births.[13][1] The most frequently ...
[128]
Incidence, Prevalence, Diagnostic Delay, and Clinical Presentation ...
The prevalence of 46,XY females was 6.4 per 100 000 live born females, and for AIS and gonadal dysgenesis, it was 4.1 and 1.5 per 100 000, respectively.
[129]
A Case of Female Pseudohermaphroditism Caused by Aromatase ...
Female pseudohermaphroditism is caused by several etiologies. Here we report a case of aromatase deficiency who showed ambiguous genitalia and maternal ...Missing: definition prevalence
[130]
Testicular differentiation in 46,XX DSD: an overview of genetic causes
In rare conditions, testicular tissue can develop into an XX gonad, resulting in the condition called 46,XX ovotesticular or testicular DSD. Clinical ...
[131]
Partial deletion of DMRT1 causes 46,XY ovotesticular ... - PubMed
In a subset of patients, ovotesticular DSD is caused by 46,XX/46,XY chimerism or mosaicism. To date, only a few monogenetic causes are known to be associated ...
[132]
The Natural History of a Man With Ovotesticular 46,XX DSD Caused ...
Aug 28, 2019 · Other 46,XX testicular or ovotesticular DSDs result from mutations in pro-ovary/antitestis genes of the WNT4/RSPO1 signaling pathway, including ...Abstract · Case Report · Discussion
[133]
Errors in Genital Differentiation - College of Medicine
Four different enzyme defects in the synthesis of testosterone commonly result in male pseudohermaphroditism. Three of the defects involve enzymes that are also ...
[134]
Differences (Disorders) of Sex Development (DSDs)
Nov 20, 2023 · DSDs may be caused by virilization of a child with 46,XX or undervirilization of a child with 46,XY. Some individuals with DSDs have genetic ...Background · Pathophysiology · Etiology · Epidemiology
[135]
Intersex - UF Health
Congenital adrenal hyperplasia. This is the most common cause of 46,XX DSD. · Male hormones · Male hormone-producing tumors in the mother. · Aromatase deficiency.<|separator|>
[136]
Disorders of Sex Development: Classification, Review, and Impact ...
Anomalies in sex determination without sex ambiguity include gonadal dysgenesis, polysomies, male XX, and Klinefelter syndrome.
[137]
Disorders of Sexual Differentiation | UCSF Department of Urology
What causes disorders of sex development? DSDs occur because of variations in the genes that control sexual development or because a person has an underlying ...
[138]
Ovotesticular disorder of sex development in a 46 XY adolescent - NIH
The prevalence of ovotestis is estimated to be less than 1:20,000, and approximately 500 individuals have been reported to date [7]. Sex ambiguity is often ...
[139]
Ovotesticular Disorder of Sex Development: An Unusual Presentation
Jul 12, 2019 · Ovotesticular DSD is characterized by the simultaneous presence of both ovarian and testicular tissues ... ovotesticular DSD is a 46, XX karyotype ...True Hermaphroditism · Case Report · Discussion
[140]
True Hermaphroditism | GLOWM
True hermaphrodites (ovotesticular disorders of sex development) have ovarian as well as testicular tissue.
[141]
True hermaphroditism—the importance of ultrasonic assessment
Jun 6, 2005 · Diagnostic investigation of hermaphroditism involves ultrasound examination of the gonads, karyotype analysis and histological studies.
[142]
Reliable Endocrine Test with Human Menopausal Gonadotropins for ...
TRUE hermaphroditism is a clinical condition in which an individual possesses both ovarian and testicular tissues, either in separate gonads or in one gonad ( ...<|separator|>
[143]
Pubertal outcomes and sex of rearing of patients with ovotesticular ...
Dec 31, 2019 · In female-assigned patients with ovotesticular DSD, menstruation is expected in 50% of cases with well-developed ovarian tissue [23]. Thus, ...
[144]
Challenges in Management of Ovotesticular Differences in Sex ...
Apr 18, 2024 · Ovotesticular DSD is the rarest variant of DSD where both ovarian and testicular tissues co-exist in an individual. Ambiguous genitalia may ...<|control11|><|separator|>
[145]
Long-term outcome of ovotesticular disorder of sex development
Jan 23, 2011 · Conclusions: According to our experience, most families in Japan desire early genital surgery in the case of ovotesticular DSD.
[146]
[PDF] Evolutionary Perspectives on Hermaphroditism in Fishes
Alternative types of hermaphroditism have different evolutionary paths, and modern evolutionary theory has identified some of the causes and implications ...<|separator|>
[147]
Phylogenetic Perspectives on the Evolution of Functional ...
Jul 1, 2013 · Thus, simultaneous hermaphroditism tends to be found only in species existing at very low densities (Tomlinson 1966; Ghiselin 1969), or in ...<|control11|><|separator|>
[148]
Modeling the evolution of waiting time to selfing in hermaphrodites
Nov 24, 2022 · We use an individual-based model and a mathematical approximation to explore how delayed selfing evolves in response to density and density fluctuations.
[149]
Sequential hermaphroditism and the size-advantage hypothesis
The hypothesis predicts that reproductive success will increase less with body size for males than for females, eventually promoting sex change in males.
[150]
A COMPARATIVE ANALYSIS OF SEX CHANGE IN LABRIDAE ...
Aug 3, 2010 · The main body of theory that predicts the conditions favoring sequential hermaphroditism is called “the size advantage hypothesis” (SAH; ...
[151]
Switches, stability and reversals in the evolutionary history of sexual ...
May 30, 2022 · While all hermaphroditic forms revert quickly to gonochorism, protogyny and simultaneous hermaphroditism are evolutionarily more stable than protandry.
[152]
(PDF) The evolution of hermaphroditism - ResearchGate
Aug 6, 2025 · Sex allocation theory for simultaneous hermaphrodites has focused primarily on the effects of sperm competition, but the role of mate choice ...
[153]
Simultaneous hermaphroditism, tit-for-tat, and the evolutionary ...
It is a form of delayed reciprocity in which individuals give up eggs to be fertilized in exchange for the opportunity to fertilize the eggs of a partner.
[154]
Macroevolutionary patterns in marine hermaphroditism | Evolution
Hermaphroditism, in which individuals produce both male and female gametes in their lifetime, occurs in almost all higher plants (95%) and around a third of ...
[155]
Testing the Low-density Hypothesis for Reversed Sex Change in ...
Mar 13, 2014 · Therefore, low density should be a key factor in the evolution of the male-to-female sex change in both monogamous and polygynous species.
[156]
Sexual competition and the evolution of hermaphroditism
The low density model produced by Tomlinson to describe the evolution of hermaphroditism is shown to undervalue the level of gain to hermaphrodites in small ...
[157]
SEX ALLOCATION AND MALE FITNESS GAIN IN A COLONIAL ...
... hermaphroditism; relaxed sperm competition in low density populations might also be required. In free-spawning marine organisms, males cannot control access ...<|control11|><|separator|>
[158]
Evolution of Self-fertilization in Hermaphrodites : an Animal ... - ANR
Self-fertilization in hermaphrodites, using their own sperm, can lead to efficient gene transmission but low offspring survival. It may be favored by low mate ...<|separator|>
[159]
Experimental Evidence for the Negative Effects of Self-Fertilization ...
Jan 23, 2017 · Reduced mate availability leads to evolution of self-fertilization and purging of inbreeding depression in a hermaphrodite. Evolution, 70 ...
[160]
Experimental Evidence for the Negative Effects of Self-Fertilization ...
Dec 29, 2016 · High inbreeding depression results in low population fitness and demographic risks but also heightens selective interference effects as ...
[161]
Self Fertilization - an overview | ScienceDirect Topics
This reproductive strategy can lead to inbreeding depression, which has prompted the evolution of mechanisms, such as self-incompatibility, to prevent it. AI ...
[162]
Sexual Conflict in Hermaphrodites - PMC - PubMed Central - NIH
Sexual conflicts over mating (“mating conflicts”) in simultaneous hermaphrodites relate to asymmetries between acting as a sperm donor or sperm recipient in the ...
[163]
(PDF) Sexual Conflict in Hermaphrodites - ResearchGate
Aug 6, 2025 · These include conflicts over the timing of sex change in sequential hermaphrodites, and in simultaneous hermaphrodites, over both sex roles and ...
[164]
Sexual conflict over mating and fertilization: an overview - Journals
While there were appreciable costs (reduced mobility, increased predation risk and time/energy costs), no significant genetic benefits could be detected.<|separator|>
[165]
Inbreeding depression under mixed outcrossing, self-fertilization ...
May 17, 2016 · We show that for a given rate of inbreeding, sib-mating is more efficient at purging inbreeding depression than selfing.
[166]
Reduced Mate Availability Leads to Evolution of Self-Fertilization ...
This should trigger a purge of inbreeding depression, which in turn encourages individuals to self-fertilize more often and finally to reduce male allocation.
[167]
Reduced mate availability leads to evolution of self-fertilization and ...
This should trigger a purge of inbreeding depression, which in turn encourages individuals to self-fertilize more often and finally to reduce male allocation.
[168]
Negative correlation between male allocation and rate of self ...
For hermaphrodites practicing some self-fertilization, theory predicts that higher population-level selfing rates should select for lower proportional ...
[169]
Dioecy Is Associated with High Genetic Diversity and Adaptation ...
We show that dioecy is associated with increased genetic diversity, as well as higher selection efficacy both against deleterious mutations and for beneficial ...
[170]
Sex Allocation: Evolution to and from Dioecy - Cell Press
A species can go all the way to dioecy via the gynodioecy pathway as females increase in frequency to 50% of the population and the hermaphrodites shift their ...
[171]
[PDF] the role of androdioecy and gynodioecy in mediating evolutionary ...
Evolutionary transitions from dioecy to hermaphroditism (or vice versa) have occurred frequently in animals, but few studies suggest the advantage of such ...
[172]
An explanation for the prevalence of XY over ZW sex determination ...
We show that when dioecy evolves from hermaphroditism, selection acts on dominance at the new sex-determining locus to favor XY over ZW sex determination.
[173]
A model for the gradual evolution of dioecy and heterogametic sex ...
Feb 27, 2024 · One proposition is that this evolution occurs in two steps, with the initial invasion of a male-sterility mutation at one locus followed by ...
[174]
Transition model for the hermaphroditism-dioecy continuum in ...
If the number of males decreased with increasing pollen transport efficiency, hermaphroditic individuals emerged in the population (establishment of trioecy).
[175]
Report The rapid dissolution of dioecy by experimental evolution
Oct 24, 2020 · Our study thus validates a mechanism for the rapid dissolution of dioecy and the evolution of functional hermaphroditism under conditions that may frequently ...<|control11|><|separator|>
[176]
Evolutionary Transitions Between Hermaphroditism and Dioecy in ...
Aug 6, 2025 · Hermaphroditism is typically associated with a sedentary existence, whereas dioecy is associated with mobility. This pattern is reflected within ...
[177]
Evolutionary Transitions Between Hermaphroditism and Dioecy in ...
Nov 2, 2022 · This paper discusses the evolutionary transitions between hermaphroditism and dioecy in animals and plants.
[178]
Transitions between Sexual Systems: Understanding the ...
Transitions between Sexual Systems: Understanding the Mechanisms of, and Pathways between, Dioecy, Hermaphroditism and Other Sexual Systems.
[179]
Gender Dysphoria in a Patient With Ovotesticular Disorder of Sex ...
Dec 22, 2023 · Optimal management of patients with OT-DSD should involve multidisciplinary teams, including endocrinology, surgery, and mental health care.Abstract · Introduction · Treatment · Discussion
[180]
Evaluation and treatment for ovotesticular disorder of sex ...
Mar 28, 2017 · The aim of this study is to review and present the clinical features and process of evaluation and treatment for OT-DSD in a single center in recent years in ...
[181]
Surgery for intersex - PMC - NIH
Associated with the above concerns is an increasing body of evidence, anecdotal and from support groups, that results of genital surgery are poor. There are ...
[182]
“I Want to Be Like Nature Made Me”: Medically Unnecessary ...
Jul 25, 2017 · Some medical practitioners claim (they admit, without strong evidence) that surgical procedures to “fix” intersex bodies have improved in recent ...
[183]
The long-term followup of 33 cases of true hermaphroditism - PubMed
Conservative gonadal surgery is the procedure of choice after a diagnosis of true hermaphroditism. Continued followup is necessary because of the multiple ...
[184]
The Long-Term Followup of 33 Cases of True Hermaphroditism
Conservative gonadal surgery is the procedure of choice after a diagnosis of true hermaphroditism. Continued followup is necessary because of the multiple ...Missing: interventions controversies<|separator|>
[185]
Ovotesticular Difference of Sex Development: Genetic Background ...
Sep 1, 2021 · Management of ovotesticular DSD has changed in recent years, prioritizing the child's future right for autonomy and self-determination.
[186]
[PDF] Position Statement on Genital Surgery in Individuals with ...
This position statement addresses surgical management for patients with differences of sex development (DSD)* and intersex traits and advocates for a process ...
[187]
Controversies on Timing of Sex Assignment and Surgery in ... - NIH
Jan 10, 2019 · Although the timing of surgery remains controversial, recent evidence suggests that male reconstruction should be performed between 6 and 18 months of age.
[188]
SPU Consensus statement 2020 - Management of ... - ESPU
Banning surgery for all patients with DSD conditions is equally as harmful to individualized care as demanding surgery for all patients with DSD conditions.
[189]
Surgeries on Intersex Infants are Bad Medicine
Jul 1, 2021 · These surgeries can result in scarring, chronic pain, chronic incontinence, loss of sexual sensation, sterilization, inaccurate gender ...
[190]
Perspectives on conducting “sex-normalising” intersex surgeries ...
Aug 28, 2024 · The surgical correction should be performed as early as possible to allow for good development of the patient's sexual identity […] Several ...
[191]
A Call to Update Standard of Care for Children With Differences in ...
This article highlights recent data from the DSD-LIFE Study and considers whether and to what extent they support deferral.
[192]
Consensus statement on management of intersex disorders - NIH
Current recommendations are testicular biopsy at puberty seeking signs of the premalignant lesion termed carcinoma in situ or undifferentiated intratubular germ ...
[193]
The Emergence and Control of Intersexuality in Medical Discourse
The completion of the transition from the hermaphrodite to the intersexual was followed in the twentieth century by treatment of intersexuality based ...
[194]
Thinking beyond the binary: The history of intersex people in the ...
Nov 8, 2018 · Initially, intersex people were referred to as “hermaphrodites,” as coined by Greek physician Hippocrates. This term, however, implies that “a ...
[195]
What's the history behind the intersex rights movement?
(The conflation of sex, sexual orientation, and gender expression becomes clear in the 1890s use of the term “psychic hermaphroditism” to refer to gay men, and ...
[196]
Changing the Nomenclature/Taxonomy for Intersex - Alice Dreger
Apr 13, 2022 · Changing the Nomenclature/Taxonomy for Intersex: A Scientific and Clinical Rationale. by Alice Dreger, Cheryl Chase, Aron Sousa, Joel Frader ...
[197]
Making sense of 'Intersex' and 'DSD': how laypeople understand and ...
Parents particularly reported concerns that 'Intersex' conflated sex and gender, drew attention to genitalia or implied a mixture of genitalia, which is ...
[198]
Intersex Variations, Human Rights, and the International ... - NIH
Objections to the language of “disorders of sex development” began immediately after it was clinically adopted in 2006 and have continued to the present time.
[199]
Changing Paradigms in Intersex Management: Legal, Ethical ... - NIH
The older terminology, with phrasing such as “hermaphrodite” and “pseudohermaphrodite,” was felt to be pejorative, confusing, and stigmatizing. The new ...
[200]
Public understanding of intersex: an update on recent findings - Nature
Jan 14, 2022 · Surgical interventions on infants with intersex characteristics are considered justified by some on the grounds that they carry a high risk ...Missing: outcomes | Show results with:outcomes
[201]
46 XY Ovotesticular Disorder: A Rare Case Report with... - LWW
Ovotesticular DSD has an incidence of <10% of all DSDs and the overall incidence of 1/100,000 live births.[1] In this disorder, both ovarian and testicular ...Case Report · Discussion · Conclusion
[202]
“Intersex” Does not Violate the Sex Binary - PMC - NIH
May 18, 2023 · Murphy's (2019) thesis that “intersex” challenges the paradigm of sexual dimorphism, the thesis that human beings are exclusively either male ...
[203]
Sex is a Biological Trait of Medical Significance
The 0.02% of people with disorders of sex development (DSD), more commonly referred to as intersex conditions, represent males and females with congenital ...
[204]
46, XX Ovotesticular disorder of sex development (true ... - NIH
Oct 2, 2020 · Ovotesticular DSD (OT-DSD), previously known as true hermaphroditism, describes individuals who have both testicular and ovarian tissues, with ...