Actually, now that you bring it up, has anyone tested to what extent sexual orientation is influenced by by exposure to cultural materials that take one or another stance?

It's very well-documented that some people are going to be gay "no matter what". And of course a lot of people are straight "no matter what". And some are bi, or something else.

But did we actually check and rule out that there is a subpopulation who will happily be what culture tells them to be, so if they have a heavy exposure to books that are all, "be gay, it's so cool!" they'll be gay, and if books are all, "be straight, gay is so OMG I can't even" they'll be straight?

It just occurred to me that although I've seen evidence for all the other things, I've never seen this addressed in an experimentally satisfying way.