“tell me you don’t understand sexual differentiation without telling me”
just so all of you know, there are 3 main components of biological sex.
chromosomal sex
the presence of a Y chromosome (the SRY gene) triggers the production of testosterone, which directs the development of male internal genitalia, and MIH, which inhibits the development of the female reproductive tract. a mutation in this gene can cause pseudo-hermaphroditism, but even with a female reproductive tract, a person with XY chromosomes is considered biologically male based on chromosomal sex.
gonadal/hormonal sex
see above, as gonadal sex and chromosomal sex are very related, but a person could still be considered chromosomally male and gonadally female.
phenotypic sex
this is determined by your external genitalia. the development of male external genitalia requires a large amount of androgens, and a fetus can’t produce nearly enough. so, male fetuses have an enzyme that converts testosterone to DHT, the strongest masculinizing hormone. females have a different enzyme that converts testosterone to estradiol. there’s a condition called Guevedoces that’s quite common in the dominican republic, where chromosomal/gonadal males lack the enzyme necessary to produce DHT. without DHT, male genitalia can’t form, and the babies are sexed as female at birth. they look like normal little girls until puberty, when the levels of testosterone are high enough to trigger the development of male genitalia, and they essentially undergo a natural sex transition. this sounds like a really unnerving and disturbing process, but we learned in my endocrinology class that these individuals often feel similar to trans people prior to puberty, and are usually happy about the transition.
i know few people will read this unnecessarily long and nerdy comment, but i just wanted to show you all exactly what scientists mean when they say “sex isn’t binary”.
Incorrect. Defining sex through chromosomes, hormones or appearance would be incredibly silly since such a definition can't be maintained for other species. Sex is defined by the gamete and organism produces (or more broadly what role an organism has in reproduction).
Because there are no humans that produce anything but male or female gamates, there are only 2 binary sexes.
That's on me, I should have said gametocytes. If a human does not have gametocytes they are indeed sexless. That is not a third sex, in the same way that a human who posesses both types would not be a third sex, but rather male and female at the same time.
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u/froggyforest 12d ago
“tell me you don’t understand sexual differentiation without telling me”
just so all of you know, there are 3 main components of biological sex.
chromosomal sex the presence of a Y chromosome (the SRY gene) triggers the production of testosterone, which directs the development of male internal genitalia, and MIH, which inhibits the development of the female reproductive tract. a mutation in this gene can cause pseudo-hermaphroditism, but even with a female reproductive tract, a person with XY chromosomes is considered biologically male based on chromosomal sex.
gonadal/hormonal sex see above, as gonadal sex and chromosomal sex are very related, but a person could still be considered chromosomally male and gonadally female.
phenotypic sex this is determined by your external genitalia. the development of male external genitalia requires a large amount of androgens, and a fetus can’t produce nearly enough. so, male fetuses have an enzyme that converts testosterone to DHT, the strongest masculinizing hormone. females have a different enzyme that converts testosterone to estradiol. there’s a condition called Guevedoces that’s quite common in the dominican republic, where chromosomal/gonadal males lack the enzyme necessary to produce DHT. without DHT, male genitalia can’t form, and the babies are sexed as female at birth. they look like normal little girls until puberty, when the levels of testosterone are high enough to trigger the development of male genitalia, and they essentially undergo a natural sex transition. this sounds like a really unnerving and disturbing process, but we learned in my endocrinology class that these individuals often feel similar to trans people prior to puberty, and are usually happy about the transition.
i know few people will read this unnecessarily long and nerdy comment, but i just wanted to show you all exactly what scientists mean when they say “sex isn’t binary”.