OK, I misunderstood you. Thank you for clarifying.

I am not saying that because people find it difficult or impossible to change their sexual orientation, they “must” have been born with it. You are correct in that argument being a non-sequitur, in that early postnatal factors are one possibility – although I don’t think the evidence supports them. Instead, I believe people are born with it and that is why it is difficult or impossible to change it. Has it been “proven” that people are born homosexual or heterosexual? No, and I don’t think it ever will be proven that people are born gay, or straight for that matter. But, my bias is that one is born with one’s sexual orientation.

Regarding your second point, I do not suggest that because no postnatal factor has been identified it is “therefore” prenatal. I raise that point because Exodus and various evangelical groups argue it “is” postnatal, yet they have no evidence to identify any specific cause, even though they explicitly mention quite a few. In other words, I raise the issue because they are inconsistent in their treatment of the evidence. They explicitly and confidently state certain postnatal factors “are” the cause of homosexuality, yet there is no good evidence. Meanwhile, they are extremely particular in how they treat any and all evidence suggesting a prenatal cause. If they were consistent in their standards they would have to relinquish their claims for postnatal causes. That is my motivation for my comment. I certainly take responsibility for not being as explicit as I should have been.
Regards,
Patrick

Toward the end of the third part of his review of the Jones/Yarhouse book, Mr. Chapman seems to imply that, because people find it difficult or impossible to change their sexual orientation, they must have been born with it. This is a non-sequitur; the effects of early childhood experience could be just as deep and irreversible as biology.

Mr. Chapman also seems to be implying that the alleged fact that scientific studies have not identified any postnatal causal factor also shows that homosexuality must be inborn. Whether science has shown that postnatal factors are involved may depend upon what assumptions one interprets it with.

Some studies have shown a rough and inexact correlation between homosexuality and particular family structures. One can argue that, because the correlation is imperfect, parental behaviour cannot possibly influence the development of homosexuality, but this would be equally as unreasonable as arguing that, because there is only an imperfect correlation between homosexuality and any gene or group of genes, genetic factors are unimportant.

The evidence of prenatal influences may perhaps be stronger than the evidence of postnatal influences, but only in relative terms.