Excerpt from The Hastings Center:

Discussions and debates over the origins of homosexuality have tended to focus on two possibilities: you’re either gay because you’ve got a ”gay gene,” or you’re gay because of some aspect of your upbringing.

(The latter option is usually imagined to involve something nasty, like a pedophilic priest.) These two options—gene-gay and turned-gay—fit neatly in the (yawn) nature-nurture debate, and that
probably explains why almost everyone seems to keep ignoring a third option, one for which there is astoundingly robust data: womb-gay.