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Comment by mfoy_ | Hacker News Reader

Huh... I wonder if there could be some sort of intervention therapy that could keep them a girl, in that case, or if it's really set in stone that they will transform.

If so, there could actually be a sort of "third sex" on the horizon. It's been explored quite a bit in sci-fi tropes, but amazing that it's actually (kind of) real!

Imagine if you literally got to choose your sex, with no preset arrangement... you were just a "third gender" type, then elect to go through either male hormone or female hormone therapy depending on your druthers.

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But it looks like they really aren't girls. This seems to be the delayed development of biological structures in a classic xy male. In an animal population this might be an advantage, hiding potential future rivals from older dominate males. We dont call girls a third sex simply because thier breasts dont develop until puberty. We call that normal. But perhaps all children are the "third sex" until they show all the classic structures.

Well, the idea is that boys and girls are actually anatomically identical in the womb and then various hormones / enzymes / whatever make the various base structures develop into what we'd recognize as either male or female sex organs.

So imagine if there was a simple way to delay that process until adolescence, when children could choose for themselves whether they wanted male or female anatomies.

Maybe they could choose anatomies. But they can't choose the part they play in reproduction later. If they choose an anatomy discordant with their genetic gender, it can make reproduction tricky.

Assuming you could get a pair of working ovaries with male chromosomes... what would happen? I really don't know enough about biology or genetics...

Or is the issue that with male chromosomes it's "tricky" to get working ovaries?

But what if it's not the typical transgender surgery, but actually having the gonads and tubercle turn into ovaries and clitoris instead of testicles and penis?

> Assuming you could get a pair of working ovaries with male chromosomes... what would happen?

I imagine it would produce about half X-ovums and half Y-ovums. X-ovums should be normal, Y-ovums might not be viable at all.

If they were, Y-spermatozoons could probably not fertilise them, or in any case it would fail rather fast without developing into a viable embryo. X-spermatozoons could fertilise them to produce male embryos.

Producing working ovaries with male chromosomes is the most unlikely step, but otherwise it seems like it should work provided the biological machinery is there to support pregnancy.

I strongly suspect that Y-ovums would not be viable at all. There's a lot on the X chromosome that is pretty vital. How Y-spermatozoons get away with it I'm not quite sure.

Genetic males have an X chromosome, so they have everything necessary to make ovaries. The issue is that the Y chromosome has the SRY gene [1], and that single gene is more or less responsible for kicking off the whole process of developing male genitalia in a fetus. That gene can get displaced off of the normal Y-chromosome and onto an X-chromosome resulting in XX Males [2] or XY Females [3]. Both conditions invariably result in sterility, though outwardly they appear mostly normal (XX Males externally look male, XY Females externally look female).

That said, the fact that one gene seems to have so much effect suggests it's plausible that in the future we might be able to do something to make those individuals fertile, or to enable genital reconstruction surgeries for transgender people that enable new fertility.

Note that much of this may be oversimplified, so any experts can feel free to apply some pedantry to the finer details.

[1] https://en.wikipedia.org/wiki/Testis-determining_factor [2] https://en.wikipedia.org/wiki/XX_male_syndrome [3] https://en.wikipedia.org/wiki/XY_gonadal_dysgenesis

That's not such a big problem anymore. Science!

More seriously, I'd say their personal preference should be the most important. It's not like we have a shortage of people.

By the time they grow up in vitro gametogenesis will probably be viable and affordable.

https://www.google.com/amp/s/mobile.nytimes.com/2017/05/16/h...

This already exists in Samoan culture outside the kind of medical intervention you're describing:

https://en.m.wikipedia.org/wiki/Fa%27afafine

But it's not really viewed as a "choice." Samoan society is just arranged differently to reflect the more variable realities of gender.

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