This reminds me of Industrial music pioneer Genesis P Orridge who went through a lot of painful surgery to become what is neither "male" or "female" in gender, but rather "alien sex". Sorry if its off-topic just bringing that on.
I do believe gender is part social construct part biological (there are even evidence that shows that men and women have different mentalities), however this never takes into account that things like hormones and libido can do to people to make them "choose" another sexuality for themselves, largely sexuality is a social construct too, these days and identity (and i'm against identity politics).
Really it shouldn't matter what sexuality people identify with, i always fail to understand what is so frightening about homosexuality (homophobia - the fear of homosexuality), however that word is most often means "hatred" and not "fear", i believe its a cultural thing, Christianity, Islam, and Judaism are all lines of the Abrahamic faith, which is what has shaped modern culture and beliefs, however if you were to go down to the pagan era, one would notice that the type of conservatism that we know of today didn't really exist, back then it was pretty much open for everything, slavery, pedophilia, bestiality, etc, there were no "social norms" in the way that we know them now. At least thats how i see it. End of rant.