Yesterday morning, I read a piece by Douglas Wilson on same-sex marriage; Wilson is a conservative Christian writing from a Calvinist perspective. (I found a link to this piece on the headline-aggregation site realclearreligion.org.) Part of Wilson's discussion focused on the debate as to whether homosexuality is genetic, part of one's nature. He argued that even if homosexuality is inborn, it is still sinful---he said that if were shown the gay gene through a microscope, his reaction would have been: "There it was, with my own eyes I saw it! Scientific proof of total depravity ... a little black twisty thing." He also says that sexual desire is indisputably genetic, but this does not mean the subject is not responsible for his lustful thoughts and actions. I was prompted to post the following comment:
I realized yesterday why conservative Christians have already lost the argument and lost the war: It's not because there's a gay gene that causes homosexuality (there probably isn't). It's simply because 40 years ago, the American Psychiatric Association determined that homosexuality is not a mental illness or a character disorder. Now all the relevant major professional scientific and medical organizations agree with this determination. This immediately undercuts any attempt to argue that homosexuality is destructive, unhealthy, etc; that is, that homosexuality has the attributes we expect of sin. So once the scientific and medical community decided that homosexuality is normal and natural, it was only a matter of time until full acceptance of gay people and same-sex relationships.
Now conservatives are still trying to argue that homosexuality actually is unhealthy and that gay people cannot achieve happiness by being gay. But by doing so, they are arguing against established science, and to a younger generation that is much more accepting of gay people, this comes across much the same as creationists arguing against evolution. This can only harm Christian groups that continue to go down this path: The younger generation is increasingly alienated from religion (the fraction of young people that are "nones", unaffiliated with religion, is high and increasing), and one key reason is that they regard conservative religion as intolerant on this issue.