|Classification and external resources|
Pseudohermaphroditism, or pseudo-hermaphroditism, is the condition in which an organism is born with primary sex characteristics of one sex but develops the secondary sex characteristics that are different from what would be expected on the basis of the gonadal tissue (ovary or testis).
In some cases, the external sex organs look intermediate between a typical clitoris or penis. In other cases, the external sex organs have an appearance that would be expected to be seen with the "opposite" gonadal tissue. Because of this, pseudohermaphroditism is sometimes not identified until puberty. It is possible for the condition to be undetected until adulthood.
The term "male pseudohermaphrodite" is used when a testis is present, and the term "female pseudohermaphrodite" is used when an ovary is present. The term "true" hermaphrodite is reserved for the very rare cases where both ovarian and testicular tissue are present. (Whether or not that term would be appropriate when ovotestes are found, or only when distinct ovaries and testes are found, is not well defined.)
Sex determination and differentiation is generalized with chromosomal sex during fertilization. At early stages, phenotypic sex does not match chromosomal sex—until later during intrauterine development, sexual maturation is reached. During intrauterine development, females change to male with the testes moving down from a blind vaginal pouch with a developing scrotum, as well as a penis which initially resembled a clitoris. What seems like a female phenotype is altered by increased testosterone secretion levels secretion.
Mutations affecting the androgen receptor (AR) gene may cause either complete or partial androgen insensitivity syndrome. Androgen, a hormone used to describe a group of sex steroid hormones, is responsible for affecting male pseudohermaphroditism. The differentiation of the fetus as male takes place during the sixth or seventh week of gestation. The development is directed by the testicular determining factor: the gene SRY (sex determining region on Y chromosome). Throughout 9th to 13th week, the development of a male genitalia is dependent upon the conversion of testosterone to the more potent androgen by the action of 5α-reductase within the target tissues of the genitalia. A type of internal male pseudohermaphroditism is Persistent Müllerian duct syndrome, which is developed through synthesis of Müllerian-inhibiting factor defects. In such instances, duct derivatives are now in 46XY males—this includes the uterus, fallopian tubes, and upper vagina. These individuals with a hernia sac and bowel loops were found with duct derivatives as well as testes.
A study on a male pseudohermaphrodite kitten showed there was a combination of gastrointestinal and urogenital congenital abnormalities. It was confirmed to have type II atresia ani and rectovaginal fistula that is associated with male pseudohermaphroditism.
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Use of the term "pseudohermaphroditism" can be problematic, and is now considered redundant. The term "pseudohermaphroditism" was created by Edwin Klebs in 1876, long before the genetic roles of the X chromosome and Y chromosome and the social components of gender identity were well characterized, which is why the term is usually used to describe the dissonance between gonadal histology and external genital appearance.
The term "intersexuality" was introduced by Richard Goldschmidt in 1923. However, the term "intersex" has also been challenged; the Lawson Wilkins Pediatric Endocrine Society and the European Society for Pediatric Endocrinology have adopted a nomenclature system based on disorders of sex development, which covers "congenital conditions in which development of chromosomal, gonadal, or anatomical sex is atypical" and thus replaces many disparate terms, including but not limited to those based on "hermaphrodite."
One example of the challenges involved in the use of the term is the case of women with Complete Androgen Insensitivity Syndrome (CAIS). These women often have primary and secondary sexual characteristics typical of other women; however, they are genetically XY and have internal testes, rather than ovaries. They have the same likelihood of a genetically XX woman of enjoying sexual pleasure but are unable to biologically reproduce. Their sexuality (homosexual, heterosexual, bisexual etc.) is unrelated to this syndrome. However scientifically precise the description "male" pseudohermaphrodite may be for such women, it is clearly socially inappropriate. CAIS is considered little better by some, as the S for syndrome in CAIS does not accord with the "normality" many CAIS women feel about their bodies.
In human beings, the sex status is defined at four levels: chromosomal (XY; XX), internal organs (ovaries; testicles), external organs (breasts, vulva + vagina; penis), and psyche (sexual identity). In a XX human the default development process results in a female. In a XY human a set of genes on the Y chromosome trigger a cascade of events normally resulting in a male. A complete female or male developmental process entails the expression of female and male sex hormones, respectively, and of their corresponding receptors in the target tissues. Without these hormones and their receptors, the internal and external sex organs, and psyche, will not develop as expected. Sex hormones, their receptors, and downstream signal transduction proteins are coded by genes that may be genetically defective.
All these factors mean that genetic mutations can block the sexual development process at three stages: (a) before the development of the internal sex organs; (b) after the development of the internal sex organs but before the development of external sex organs; and (c) after the development of external sex organs but before the maturation of the sexual component of the psyche.
While in (a) the XY human will be indistinguishable anatomically and psychologically from a female; in (b) the individual may either be born with ambiguous external genitals or have genitals apparently in the normal range at birth but, at pubertal age, not develop secondary sexual characteristics at all or develop secondary sexual characteristics that do not match the external genitals; and in (c) the individual will be transgendered (formerly referred to as transsexual).
There are other intersexual states that are not the result of the genetic configurations above.
In particular, where either the individual is a chimera - resulting from a fusion of two distinct embryos, one male and one female, during fetal development (not a genetic mosaic), or the individual contains duplicated chromosomes in the genome (XXY; XXXY). In the former case some tissues will be in the XX and others in the XY configuration; in the latter, all cells contain the Y chromosome and may or may not use it. This is a gynandromorph, which has both female and male characteristics at all four levels and may have either ambiguous sex organs (the XY/XX configuration may not be evenly distributed throughout the body) or unambiguous male and female sex organs (hermaphrodite).
John Money is perhaps the best-known early researcher in this area. His doctoral thesis was titled Hermaphroditism: An Inquiry into the Nature of a Human Paradox, and awarded by Harvard University in 1952.
Money's general views on gender identity as something learned during childhood were later directly contradicted by a biography published in 2001 by one of his former patients, David Reimer. Among the repercussions was damage to John Money's reputation. Not only had his theory of gender plasticity been dealt a severe blow but Reimer's biography described bizarrely unpleasant childhood therapy sessions, and implied that Money had ignored or concealed the developing evidence that Reimer's reassignment to female was not going well. Money's defenders have suggested that some of the allegations about the therapy sessions may have been the result of False memory syndrome. However, Reimer's brother and mother both agreed that the therapy was not "working" in the sense that Reimer wasn't in any way developing a female self-image during his treatment with Dr. Money. Dr. Money never publicly stated that his conclusions were incorrect.
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- 5ARD is also known as 5-α-reductase 2 deficiency because the 5-α-reductase 2 gene is deficient
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In the 20 years since it was established that impairment of dihydrotestosterone formation is the cause of a rare form of human intersex, a wealth of information has accumulated about the genetics, endocrinology, and variable phenotypic manifestations, culminating in the cloning of cDNAs encoding two 5 alpha-reductase genes and documentation that mutations in the steroid 5 alpha-reductase 2 gene are the cause of 5 alpha-reductase deficiency. Perplexing and difficult problems remain unresolved, e.g., whether the variability in manifestations is due to variable expressions of steroid 5 alpha-reductase 1 or to effects of testosterone itself. It is also imperative to establish whether defects in steroid 5 alpha-reductase 2, perhaps in the heterozygous state, are responsible for a portion of cases of sporadic hypospadias, to determine whether 5 alpha-reductase plays a role in progesterone action in women, and to elucidate the relation between androgen action and gender role behavior
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Higher body hair with lower mesmorphism ratings were observed in Caucasian homosexual men compared with the general male population, reflecting elevated 5alpha-reductase (5alphaR) activity, and higher dihydrotestosterone-to-testosterone (DHT-to-T) ratio, in sharp contrast to 46,XY 5alphaR 2 deficiency subjects, who are often born with ambiguous, or female genitalia, but tend to grow up to be muscular, heterosexual men with very little body hair, or beard. One study also showed them scoring around dull normal IQs. A greater prevalence of liberal body hair growth in men with higher IQs and/or educational levels was also observed in several samples. The exceptions to this statistical trend are too unsettling, however. Nevertheless, the results of a number of published studies, including one showing higher DHT-to-T ratio in homosexual men, done with different objectives over a span of 80 years, together strongly support these findings. Furthermore, in an animal model, "cognitive-enhancing effects" of "5alpha-reduced androgen [metabolites]" were recently demonstrated.
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