Ages ago--I think I was in fifth or sixth grade, perhaps--the sister (or some other relative) of a friend of my aunt had a hermaphrodite baby. I wouldn't have known about it if I hadn't overheard my mother and father talking about it. Naturally everyone was shocked and horrified. But the doctors assured them it wasn't a big deal, and they'd just "fix" the male organs, leaving the baby a woman. I don't think anyone even gave thought about whether it'd feel like a woman once it hit puberty.
There've always been hermaphrodites. Most people just weren't told about them. And if one was born in the family, it was "fixed", at least in this country.
That's just one possibility. I'm sure not all trans people are hermaphrodites. Complex subject.