Or so says a Swedish study published in PNAS and by now widely mentioned throughout the press. No surprise here, at least for some cases: it had already been reported in gay rams, for instance.
My question is: what happens to all that wide sector of bisexual and ambiguous tendencies? How are their brains? Intermediate? Have it all? They certainly have not been scanned here: only homo and hetero. ----------
Update: Razib comments on another (also Swedish) study, this one on twins, that notices that the impact of genetic factors is higher in gay men (34-39%) than in lesbians (18-19%). The why of the other study was placed mostly in the womb (epigenetics) instead.