> Plus it doesn't make sense from a Christian perspective. The Roman Catholic branch and derivatives all believe everyone is genetically predisposed to sin through Adam's lineage, and that is a bad thing, and we don't have a choice in the matter. So saying homosexuality is a genetic predisposition just means it gets lumped into the rest of our fallen attributes. Making it a choice doesn't fix things either, since a choice can be intrinsically sinful.

I think that's an inescapable conclusion in traditional Christianity. That will or choice is not necessarily a component of responsibility is something we also adopt in law: involuntary manslaughter is different than premeditated murder, even though the outcome is the same. In other words, will is not essential to guilt, although the degree to which we assess punishments certainly is. I don't know what Catholicism says to that, really, but it does seem to me that the arguments concerning genetic predisposition would have failed in most conservative religious approaches because of the premise.

Even so, I think that this is a mostly ancillary concern. The real issue is that there are competing and irreconcilable views of what it means to be human. Are we human because of the bodies we inhabit? Are we human because of how we can feel about who we are? Because we can transcend our bodies? I would postulate that answering this question is an essentially religious exercise, whether your narrative comes from a biology textbook, genetic programming manual, or the Bible. But that's an opinion that is perhaps even murkier to plumb than the roots of homosexuality in human experience.