Thread by @FondOfBeetles

@FNC_Jobby2 @DrCarolHay @nytimes The 1.7% estimate comes from the work of Fausto-Sterling. She considers as "intersex" any person outside of the "Platonic ideal" of male/female, regarding gonads/genitals/chromosomes/hormones. 1/

@FNC_Jobby2 @DrCarolHay @nytimes In practice, this means that Fausto-Sterling includes in her 1.7% people who could not, by any reasonable definition that does not destroy the category entirely, be labelled as “intersex”. Here follow some examples. 2/

@FNC_Jobby2 @DrCarolHay @nytimes 1. Klinefelter syndrome (XXY). People with Klinefelter are male. They have testes, male internal genitalia and penises. They can father children with the sperm they produce. Some males with Klinefelter are so average, they don’t even know they have an XXY karyotype. 3/

@FNC_Jobby2 @DrCarolHay @nytimes 2. Jacob syndrome (XYY). People with Jacob are male, normal males, normal fertility, never likely to discover they have an XYY karyotype unless tested during other medical exams. 4/

@FNC_Jobby2 @DrCarolHay @nytimes 3. Triple X syndrome (XXX). People with Triple X are female, with ovaries, uteruses, vaginas and vulvas. Their most remarkable phenotype is “a bit tall”. 5/

@FNC_Jobby2 @DrCarolHay @nytimes 4. Turner syndrome (XO). People with Turner are female. They develop ovaries which (mostly) degenerate, and have internal and external female differentiation. Turner females can occasionally menstruate and conceive. They can carry with donor eggs. 6/

@FNC_Jobby2 @DrCarolHay @nytimes 5a. Late onset congenital adrenal hyperplasia (LOCAH). This is the biggie and accounts for 88% of the 1.7% figure (so 1.5% of the population have this). This is “too much testosterone at some point in life after reproductive development”. 7/

@FNC_Jobby2 @DrCarolHay @nytimes 5b. LOCAH does not bother males. Females are born with functional ovaries and entirely typical female internal and external genitalia. At some point in life (average age 24 years), females begin to make too much testosterone and become virilised. 8/

@FNC_Jobby2 @DrCarolHay @nytimes 5c. The level of virilisation varies - mild hirsutism, increased muscle, enlarged clitoris, cessation of ovulation. Intervention is normally pharmacological. Fertility may be compromised but these people are unambiguously female and make babies in the regular female fashion. 9/

@FNC_Jobby2 @DrCarolHay @nytimes 6. Agenesis of female reproductive tract. These people are female. They have ovaries and ovulate, but lack specific structures within their reproductive tract e.g. a uterus or vagina. In the latter case, reconstruction can allow normal conception and birth. 10/

@FNC_Jobby2 @DrCarolHay @nytimes So, once you start poking into Fausto-Sterling’s list, it becomes increasingly obvious that she was exceptionally broad with her definition of “intersex”, to the point where it becomes meaningless. 11/

@FNC_Jobby2 @DrCarolHay @nytimes Removing just the LOCAH cases leaves us with a figure of 0.2%, but even that is an overestimate when the other obvious discrepancies are subtracted. End/

@FNC_Jobby2 @DrCarolHay @nytimes I should clarify: my ‘too much testosterone...’ comment is what LOCAH results in, not that any condition of too much testosterone is called LOCAH.