As someone who knows nothing about this subject, if the cause doesn't appear to be genetic then what does that leave? Environmental? Something else?
In reality there are going to be a bunch of different factors. Genetic predisposition is certainly likely to be one of them. Environmental factors too - like the hormonal environment in the womb, which I seem to remember had some correlation. Upbringing and social factors will also play an effect - a child with a strongly homophobic upbringing is less likely to explore their sexuality and end up identifying or embracing same-sex attraction.
Also, same-sex attraction usually occurs long before any kind of "exploration", and doesn't seem to be any more controllable or malleable than heterosexuals would be able to control their attraction to the other sex.
So if somebody hides his homosexual orientation, that's not what the study would refer to as heterosexual orientation.
At no point did I say that it was uncommon for homosexual children to have homophobic parents. That obviously happens all the time.
But I think you are trying to use overly precise ideas to analyse human sexuality. It’s complex and messy and the result of many different factors. You can’t completely isolate sexual attraction from identity or social background; indeed it seems blindingly obvious to me that upbringing would have an effect on an individual’s willingness to think about, accept or acknowledge any latent same-sex attraction they experience. It can be hard for an individual who is raised to reject same-sex sexual activity as perverted or morally wrong to even consider the possibility that it’s something they might experience themselves. People ignore or reject aspects of themselves all the time.
I can’t be certain, but my experience suggests that human sexuality is probably much more fluid than we generally expect as a result of long-standing social conventions. This is something that might change as same-sex relationships lose their taboo. And maybe I’m totally wrong; maybe homosexuality is just the result of a bunch of physiological changes. I find it hard to reconcile though.
There indeed seems to be an immutable difference between those who are primarily/exclusively attracted to the same or the opposite sex. But actual behavior, affected by culture and circumstances, does make all of this more difficult.
Homosexuals are often perfectly able to "function" in heterosexual intercourse, and heterosexuals in homosexual intercourse. But the study didn't ask for that, they asked for the underlying preference. They may even have used physical measurements. Yes, there are studies where the participants are exposed to different stimuli and their arousal is measured physiologically.
Many homosexuals really don't like the Idea of their sexual identity being "fluid". It doesn't seem to be the case that people "find out" they are homosexual later in life. They usually know it in puberty, even if they may not be able to clearly articulate it.
Talking about sexual identity as fluid is very close to saying it is a choice, curable or preventable, and that idea is causing a lot of harm.
Bisexual behavior or identity is something different again. And it's not clear to me if these are homo/heterosexuals also being able to "function" in the other way, or if it is a third kind of sexual orientation. From what I know it seems to be that a lot more heterosexuals are able to feel homosexual attraction/arousal than we may think. And homosexuals, especially in the past, have led opposite-sex relationships with all the "trappings".
What in the parent comment makes you think this way (besides being an awful way to introduce an opinion)? He's just stating that someone with homophobic parents will probably be discouraged to explore, accept, or even recognize his sexual orientation. More broadly, that environmental factors will play a role.
And yes, I guess it's not more malleable than any other sexual orientation. It could happen to heterosexual children in an heterophobic society, too.
I just get the feeling that you believe homosexuality to be something that can be consciously influenced by the individual himself or his social circle. And that can be a harmful attitude.
And the suggestion that "homosexuals would behave equally badly in a heterophobic society" is at best unhelpful.
One reason: Later children in large families are more likely to be gay but the reason might be related to the mother already being exposed to hormones with earlier children. On an evolutionary scale this might make sense that the first born are more likely not to be gay as to pass on the genes but later children population control might make more sense.
Another might be hormone levels of the mother.
Another might be gene related where physical changes are different
Another might be gene related that increase gender fluidity which combined with society can shape sexuality
But we do know there isn't a single simple gene.
Sexual orientation seems to be somewhat similar, in that environmental factors, akin to chance, lead to choosing one path among several.