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''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.) Associated conditions in males include 5-α-reductase deficiency〔5ARD is also known as 5-α-reductase 2 deficiency because the 5-α-reductase 2 gene is deficient〕 from a deficiency in the male chromosome (46 XY).〔 〕〔 〕 ==Genetics== 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 levels secretion.〔Cummings, Michael R. "Human Heredity: Principles and Issues". Cengage Learning, 2011, 2009. p. 168.〕 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. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pseudohermaphroditism」の詳細全文を読む スポンサード リンク
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