What about those that didn’t undergo any trauma?
Homosexuals make up about 1% of the population. Some people place the number as high as 2%, but current research indicates that this number is too high. I think it's clear that most (if not all) of the 1% of the population which is homosexual is that way because of some form of traumatic abuse.
If you want to argue that 0.15% of the population is "born gay" you could do so, of course. Personally I find it less than compelling. The bottom line, however, is that we have no need to reshape our society, our military recruitment practices, and our definition of marriage because some infinitesimal sliver of the population thinks we should.
Tyranny by the minority is not what this country is about.
They're probably lying. I have known/met many, many homosexuals...male/female over the years. Each of them had a "story" to tell.
It follows that they would be less likely to be homosexual.
The causality is probably multifactorial: genetic variation, prenatal hormonal influence, trauma, culture, choice.