Not sure why they're making this about gender identity, in the twisted modern sense we use now. He was born with a genetic condition called Klinefelter Syndrome, which means he was born with an extra X chromosome. This results in all kinds of side effects, but primarily in ways that exhibit more feminine traits. This is a genetic basis for gender identity, which is highly different than a strictly biological man identifying as female, or vice versa. It's an edge case, and exists as its own category. It brings up interesting questions about how such an abnormality was treated in those times, culturally and socially.