Is homosexuality innate or acquired?

I recently read two articles in Slate on homosexuality, which I had somehow missed. Both are by William Saletan.

In one of the articles, Saletan discusses evidence that human sexual preference is influenced by exposure to hormones in the womb. The article points out that there are physical differences between the brains of homosexuals and heterosexuals, in "overall symmetry and amygdala activity." There are abundant links in the article, but only an abstract, not the complete original research article, is available, unless you have full access to the Proceedings of the National Academy of Sciences. (This would be true of all articles in that journal, whatever the topic.)

Saletan considers the implications, and suspects that, in time, many parents will ask for pre-natal diagnosis, and intervention to prevent hormone exposure that would make homosexuality likely in their offspring. He says that at least some conservative Christian groups would favor such treatment.

In the other article, Saletan discusses evidence that some male sheep (less than 10%) are attracted to other male sheep. Once again, the abstract, not the primary research article, is available to most readers. Again, there are differences in brain structure and activity, between "homosexual" sheep and "heterosexual" sheep.

I don't expect this research to change anyone's mind about homosexuality, but it is part of the data.

See this post for a reasonably thorough discussion of Christianity and homosexuality.

Thanks for reading.