That's assuming we even have chromosomes in the Forgotten Realms. As someone who never replays BG II without a girdle handy, I'd really be tickled if it made an appearance in BG3. But the question remains, how does magic, and established magic like the girdle, and Edwin's quest change the dynamic any story incorporating transgender characters. If I remember correctly there's even a subrace of elves who can change their sex every night. Of course because it's new to the setting, and the zeitgeist we currently live in, it's difficult not to see it overtaking any story it's added to.
A bit of an aside but for some of the same reasons I don't like the playersexual characters in BG3, the absence of a lot of these themes from Cyberpunk 2077 really irked me. Oh you don't like sexing men? I can pop down to the shop and we'll be good to go.
There are genres and settings that are actually designed to engage with certain stories, when you mix them together you're making a variation or subversion of the genre your working in to comment on another genre.
