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Sex assignment (sometimes known as gender assignment) is the discernment of the sex at the birth of a baby.〔Reiner WG (1997) Sex assignment in the neonate with intersex or inadequate genitalia. ''Archives of Pediatrics and Adolescent Medicine,'' Oct;151(10):1044-5. PMID 9343017〕 In the majority of births, a relative, midwife, nurse or physician inspects the genitalia when the baby is delivered, and gender is determined, without the expectation of ambiguity.〔Reiner WG (2002). Gender identity and sex assignment: a reappraisal for the 21st century. ''Adv Exp Med Biol.'' 2002;511:175-89; discussion 189-97. PMID 12575762〕 Assignment may also be done prior to birth through prenatal sex discernment. Even though the term ''assignment'' suggests a decision on the part of the parents or medical professionals, these adults are not literally choosing a sex to assign to the child. The act is almost universally considered an ''observation'' or ''recognition'' of an inherent aspect of a baby. In the majority of cases, the gender of rearing of the child matches the assigned gender. The act of assignment carries the implicit expectation that future gender identity will develop in the gender of anatomy, assignment, and rearing.〔Shaw, Alison; Ardener, Shirley (2005). ''Changing sex and bending gender,'' p. 21. Berghahn Books, ISBN 978-1-84545-099-1〕 In some cases, the assigned sex or one or more of these related observations and conclusions are found to be incorrect. In the case of some transgender individuals or intersex individuals, gender identity is not consistent with the assigned sex or sex of rearing.〔Diamond DA, Burns JP, Mitchell C, Lamb K, Kartashov AI, Retik AB (2006). Sex assignment for newborns with ambiguous genitalia and exposure to fetal testosterone: attitudes and practices of pediatric urologists. ''J Pediatr.'' 2006 Apr;148(4):445-9. PMID16647402〕 There have also been rare instances where parents (for a variety of reasons) have reared an anatomically typical child as if he or she were of the opposite gender. In some conditions, usually termed ''intersex'', internal anatomy may not be consistent with conclusions drawn based on observation of external anatomy.〔Mieszczak J, Houk CP, Lee PA. Assignment of the sex of rearing in the neonate with a disorder of sex development. Curr Opin Pediatr. 2009 Aug;21(4):541-7. PMID 19444113〕 ==Assignment in intersex conditions== Intersex is a broadly defined term that usually denotes the presence of atypical sex characteristics: at least some aspect of the genitalia, internal organs, gonadal tissue, or chromosomes is more typical of the other sex. When the external genitalia appear to be in between, they are described as ambiguous.〔Ora Hirsch Pescovitz, Erica A. Eugster (2004). ''Pediatric endocrinology: mechanisms, manifestations, and management,'' p. 253. Lippincott Williams & Wilkins, ISBN 978-0-7817-4059-3〕 In approximately 1 in 2,000 infants, there is enough variation in the appearance of the external genitalia to merit hesitation about appropriate assignment by the physician involved. Typical examples would be an unusually prominent clitoris in an otherwise apparently typical girl, or complete cryptorchidism or mild hypospadias in an otherwise apparently typical boy. In most of these cases, a sex is tentatively assigned and the parents told that tests will be performed to confirm the apparent sex. Typical tests in this situation might include a pelvic ultrasound to determine the presence of a uterus, a testosterone or 17-hydroxyprogesterone level, and/or a karyotype. In some of these cases a pediatric endocrinologist is consulted to confirm the tentative sex assignment. The expected assignment is usually confirmed within hours to a few days in these cases. In a much smaller proportion of cases, the process of assignment is more complex, and involves both ''determining'' what the biological aspects of sex may be and ''choosing'' the best sex assignment for the purposes of rearing the child. Approximately 1 in 20,000 infants is born with enough ambiguity that assignment becomes a more drawn-out process of multiple tests and intensive education of the parents about sexual differentiation. In some of these cases, it is clear that the child will face major discordances or abnormalities of anatomy or function as he or she grows up, and deciding upon the sex of assignment involves weighing the advantages and disadvantages of either assignment. Criteria for assignment in these cases have evolved over the decades, as our understanding of the biological factors and our diagnostic tests have improved, as surgical techniques have changed and potential complications have become clearer, and in response to the outcomes and opinions of adults who have grown up with various intersex conditions. Before the 1950s, assignment was based almost entirely on the appearance of the external genitalia. Although physicians recognized that there were conditions in which the apparent secondary sexual characteristics could develop contrary to the person's sex, and conditions in which the gonadal sex did not match that of the external genitalia, their ability to understand and diagnose such conditions in infancy was too poor to attempt to predict future development in most cases. In the 1950s, endocrinologists developed a basic understanding of the major intersex conditions such as (congenital adrenal hyperplasia (CAH), androgen insensitivity syndrome, and mixed gonadal dysgenesis. The discovery of cortisone allowed survival of infants with severe CAH for the first time. New hormone tests and karyotypes allowed more confident diagnosis in infancy and prediction of future development. Sex assignment became more than choosing a sex of rearing, but also began to include surgical treatment. Undescended testes could be retrieved. A greatly enlarged clitoris could be amputated to the usual size, but attempts to create a penis were unsuccessful. John Money and others controversially believed that children were more likely to develop a gender identity that matched sex of rearing than might be determined by chromosomes, gonads, or hormones. In the 1960s, pediatric surgeons attempted and claimed success with reconstruction of infant genitalia, especially enlargement or construction of vaginas. The view of gender as a purely social construction, and gender identity as a result of nurture rather than nature reached near-universal acceptance, especially among liberal, progressive, and academic portions of Western society. The primary goal of assignment was to choose the sex that would lead to the least inconsistency between external anatomy and assigned psyche (gender identity). This led to the recommendation that any child without a penis or with a penis too small to penetrate a vagina could be raised as a girl, taught to be a girl, and would develop a female gender identity, and that this would be the best way to minimize future discrepancy between psyche and external anatomy in those few biologically male infants unfortunate enough to be born with an irreparably defective penis (e.g., cloacal exstrophy), or to lose it to accidental trauma in early infancy. This was termed the "Optimal gender model." In the John/Joan case, John Money claimed successful ''reassignment'' at 17 months of age from male to female of a boy whose penis was destroyed during circumcision. However, this claim was later shown to be largely false, and the subject later identified as a man (see below). The recommended rules of assignment and surgery from the late 1960s until the 1990s were roughly: *Any XX infant, no matter how virilized, should be raised as a girl to preserve the chance of future fertility. A large, protruding clitoris should be reduced in size with a nerve-sparing recession or reduction rather than simple amputation. *Any undervirilized XY infant should be raised as a boy if the penis could be expected to be large enough to stand to urinate and to insert into a vagina for coitus. If it was too small or too malformed (e.g., cloacal exstrophy) for these functions, it was recommended that the baby be assigned as female, any gonads removed, a vaginal opening surgically constructed, and estrogen provided at puberty. *An infant with mixed chromosomes (e.g., mixed gonadal dysgenesis or true hermaphroditism) could be raised either way depending on appearance of genitalia and size of phallus. *Gender identity is set by 2 years of age and reassignment after that age should not be attempted unless requested by the patient. *Non-disclosure of the intersex condition to the individual on whom sex assignment treatment was conducted. Since the 1990s, a number of factors have led to changes in the recommended criteria for assignment and surgery. These factors have included: *Public disclosure by intersex individuals and organizations about unsatisfactory sexual function or incongruent gender identity, and criticism of infant surgery for "psychosocial rationales". Some have suggested that assignments be made more tentatively and surgery deferred in acknowledgement of the possibility of a desire to change gender when the child is older (see Reassignment, below) *In 1997, the rest of David Reimer's story, referred to above as John Money's John/Joan case, was made public. He was the boy who had lost his penis to a botched circumcision at 8 months in 1966, was reassigned from boy to girl at 18 months with further surgery to remove testes and estrogen treatment beginning at age 12. Although John Money had described the reassignment as a success in the 1970s, Reimer went public with his account of continuing to have a male gender identity despite the reassignment to a female sex of rearing. At age 15, Reimer reverted to living as a male. At age 38, he committed suicide. *A large proportion of XY infants born with cloacal exstrophy and raised as female from early infancy have requested reassignment to male gender in late childhood and adolescence. Recommendations in the 2000s for assignment changed as a result: *Raise nearly all XX infants with functional ovaries as female. * *The only rare exception would be completely and unambiguously virilized XX infants with CAH, who might be raised as male with genital surgery deferred. *Raise most ambiguous XY infants with testes as male unless the external genitalia are more female than male, marked androgen insensitivity is present, and testes are absent or defective. * *Raise as male any XY infant with unambiguous micropenis. * *Raise as male any XY infant with functional testes and normal androgen sensitivity but malformed or absent penis. *Raise infants with mixed gonadal tissue, true hermaphroditism, or other chromosomal abnormalities as the sex most consistent with external genitalia, since gonads are usually nonfunctional. *Gender identity is set by 1–2 years of age and reassignment after that age should not be attempted unless requested by the patient. Rationales for surgical and hormonal interventions later included rationales such as mitigation of parental distress and trauma, and improving marriage prospects. 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「Sex assignment」の詳細全文を読む スポンサード リンク
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