Hermaphroditism

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hermaphroditism

[hər′ma·frə·dīd‚iz·əm]
(physiology)
An abnormal condition, especially in humans and other higher vertebrates, in which both male and female reproductive organs are present in the individual.

Hermaphroditism

 

the presence of male and female sexual characteristics in the same individual. Hermaphroditism in animals includes hermaphroditism proper, which in turn includes natural hermaphroditism, which is characteristic of certain groups of animals, and anomalous hermaphroditism, which is found in animals that are normally dioecious.

Natural hermaphroditism is widespread among invertebrates: it is characteristic of some gastropods (Hydra), almost all flatworms (planarians, trematodes, and tapeworms), some annelids (Hirudinidea, oligochaete annelids), certain mollusks, and so on. It is characteristic of certain fishes, (bass and sea carp) among vertebrates. In natural hermaphroditism both ova and spermatozoa are formed, whereupon either both types of sex cells are capable of fertilization (functional hermaphroditism) or only one of them is so capable (afunctional hermaphroditism). Functional hermaphroditism is further subdivided into cases in which the organisms either produce predominantly one type of sex cell and only occasionally the other, or perform the role of one or the other sex, or perform the functions of males and females simultaneously, or use so-called supplementary males for fertilization. Cross-fertilization (exogamy) in hermaphroditism is ensured by nonsimultaneous development of opposite sex glands (marine crustaceans, tunicates), by sexual apparatus that prevents entry of the sperm into the female organs of the same individual (planarians, mollusks), and by the impossibility of forming zygotes of the male and female sex cells of the same individual (the ascidian Ciona intestinalis).

Anomalous (pathological) hermaphroditism is observed in all groups of the animal world, including higher vertebrate animals and humans; it may be true hermaphroditism (in which the same individual either has male and female sex glands simultaneously or has a compound gland, part of which is constructed like an ovary and part like a testicle) or pseudohermaphroditism, in which an individual has sex glands of one sex but the external sex organs and secondary sexual characteristics are entirely or partially those of the other sex. The phenomena of pseudohermaphroditism include masculine females and effeminate males.

N. A. IL’IN

Hermaphroditism in humans. A congenital defect in development, hermaphroditism in humans is characterized by the simultaneous presence of male and female sexual characteristics. In true hermaphroditism a single individual has the sex glands of both sexes (testicle and ovary); in such cases one of these is functionally active and the other is in a state of atrophy or degeneration. Rarely, both glands function; a bisexual (compound) gland may also be found. Secondary sex characteristics in hermaphroditism (appearance of the external sex organs, skeletal structure, mammary glands, type of hair distribution, voice quality, and psychology) develop according to either the male or female type or are of mixed (indeterminate) type. If the characteristics of true hermaphroditism extend not only to the sex glands but also to the internal and external sex organs and secondary sex characteristics, it is total true hermaphroditism. The psychological makeup and sexual tendencies of persons with true hermaphroditism vary in the course of their lives and are at times male and at other times female in character.

More common is pseudohermaphroditism—the noncorrespondence between the sex glands and the secondary sex characteristics. Endocrine factors and chromosomal mechanisms play a large role in sex differentiation. Disturbances of the interrelations of hormones secreted by the adrenal cortex, the sex glands, the hypophysis of mother and fetus, and the placenta all affect the proper formation of the infant’s sex in the intrauterine period, which may produce the presence of sex glands of one sex and sexual characteristics of the other. Establishing sex in pseudohermaphroditism according to external appearance and structure of the external sex organs is practically impossible. Male pseudohermaphroditism (when a boy has male sex glands and female external sex organs) may arise when there are rare feminizing tumors of the adrenal cortex of the mother, when the mother has been treated with excessive female sex hormones, or from other causes. The development in little girls of male external sex organs and other male secondary sex characteristics when ovaries, uterus, and tubes are present constitutes female pseudohermaphroditism, which arises as a result of a congenital tumor of the mother’s adrenal cortex or treatment of the mother with male hormones or certain other hormone preparations during pregnancy. Male and female pseudohermaphroditism are in turn subdivided into external, internal, and total types. The presence of male sex glands and resemblance of the external sex organs to the female type is found in external male pseudohermaphroditism; the simultaneous presence of testicles, uterus, tubes, and an underdeveloped prostate gland and seminal vesicles, in internal male pseudohermaphroditism; and a combination of improper development of external and internal sex organs, in total pseudohermaphroditism.

Hermaphroditism is treated by surgery, including plastic surgery, and with hormone therapy.

L. M. GOL’BER

Hermaphroditism in higher plants. Natural mixed sexuality is usually called monoecism in higher plants, as distinguished from dioecism. In botany the term “hermaphroditism” is most often applied only to anomalous development of stamens in female specimens of dioecious plants or of pistils in male plants. In lower plants mixed sexuality is designated as homothallism and dioecism as heterothallism.

REFERENCES

Breitman, M. Ia. Klinicheskaia semiotika i differnentsial’naia diagnostika endokrinnykh zabolevanii. [Leningrad] 1949.
Liberman, L. L. “Vrozhdennye narusheniia polovoi differentsirovki.” In Mnogotomnoe rukovodstvo po vnutrennim bolezniam, vol. 7. Edited by E. M. Tareev. Moscow, 1966. Pages 642-55.