UGH, I am SO sorry.
My son has many challenges but he knows that I am attracted to men and women (he does sometimes laugh if I am checking out another woman but I think it is because I check out more women than men)... Anyway... He also has an Aunt (actually a friend of mine from college but...) that was clearly male but identified as female when they met but is now mtf. So... sometimes in speech therapy my son has trouble with gender labels... which may or may not be connected but I am not big on gender labels anyway....
I guess what I am saying is that it doesn't matter if a child has challenges, they still need to know about such things and learn to be accepting of differences.