A reader writes:
Your reader stated, "if you choose to believe that homosexuality is chosen, and a sin, then a medical cure for homosexuality presents a legitimate challenge to that belief."
I grew up in a highly evangelical culture, and I can attest that your reader overstates the case that the finding of evidence for sexual orientation in-utero would conflict with evangelicals' beliefs. The hard belief that orientation is in no way biological was dropped years ago by nearly all evangelicals. That is why we have seen such a shift towards condemning homosexual "activity" or "relationships" instead of merely orientation. Proving that orientation can be predicted from the womb would merely solidify this trend, and do nothing to further acceptance. For the average evangelical, there simply would be no contradiction with believing "gay is bad" and also "gay is nature." In fact, it would be seen as God's gift to parents so that they could train their children to never ever act on their "temptations."
A Christian who affirms Original Sin ought not to be scandalized to learn that homosexuality may have a biological basis. That humans are compulsive sinners by nature is a core doctrine of the church and the reason why we are all in need of salvation. Indeed, the Apostle Paul chose "the flesh" as a core term in his writings about sin.
As a 23-year-old gay man raised evangelical Christian, I'd like to counter this reader.
A lot of conservative Christians have come around to the viewpoint that homosexuality may not be a simple choice. You may have been raised wrong and are trying to compensate for that - this is the current line peddled by most ex-gay groups (and, sadly, most evangelical parents with gay children). For instance, my own parents, for reasons explainable only by forced narrative and cognitive dissonance, accept this reasoning and have decided that my gayness is probably a combination of my personality and a somehow-defective upbringing, and my own subconscious response to that. But they still regard homosexuality as one of the most egregious sins known to man, just one in which those "making" the gay person bear some share of responsibility. There are lots of people who think like this, especially in the South. And although the younger generation is more accepting than their parents, quite some number of the youth have this view as well.
I just wanted to point out that their has already been some controversy within the Christian right about this. Albert Mohler, president of the Southern Baptist Theological Seminary, argued that homosexuality is probably biological in its origins, and that it should be changed in utero if possible. He does think that admitting homosexuality is a choice makes it any more acceptable:
3. Given the consequences of the Fall and the effects of human sin, we should not be surprised that such a causation or link is found. After all, the human genetic structure, along with every other aspect of creation, shows the pernicious effects of the Fall and of God’s judgment.
4. The biblical condemnation of all homosexual behaviors would not be compromised or mitigated in the least by such a discovery. The discovery of a biological factor would not change the Bible’s moral verdict on homosexual behavior.
I hope that one day Mohler, and others like him will see that there is no sin and no harm in bisexuality and homosexuality, but I am doubtful that establishing a biological explanation will sway those who take as a given that homosexuality and bisexuality are sinful.