In societies where the population is mostly naked, there is little sexual reaction to nudity.
But in a society where women’s faces are covered, there is a known sexual arousal when men see a woman’s face.
What arouses sexually is truly a learned thing, and can be modified. This is well-known, but ignored because it does not fit the “victimhood” argument.
Oxytocin is a neuromodulator hormone that promotes bonding. Among other things, it is released during orgasm.
I think that a young person's first sexual experiences have a lot to do with their future orientation, and that same-sex molestation at an early age is a major factor in whether homosexual attraction is formed.