As reported by William Saletan in a recent article entitled Brokeback Mutton, sheep producers want to know which lambs are gay for reasons of productivity, because gay rams are useless for breeding. Research to identify them through genetic or other biological tests is ongoing.
Toward the end of the article, Saletan speculates on whether such technology might be used by humans for prenatal screening and abortion of gay fetuses. He concludes that some sort of "cure" by means of genetic or hormonal alteration at an early age is a more likely scenario. This is how he describes one possible outcome:
Science will gradually convince us that sexual orientation is innate, more like skin color than character. Condemnation of homosexuality as a sin will subside, and we'll turn to two biological differences between race and sexual orientation: Homosexuality defies the aspiration to procreate with your mate, and it's easier to isolate and alter in embryonic development. We may come to view homosexuality as we do infertility -- as a disability. The rhetoric of "acceptance" will shift from liberals to conservatives. We'll inoculate our children against homosexuality out of love, not hate...
...bad ideas, such as communism and eugenics, are usually well-intended ideas that turn bad along the way.
He's got that right. If you want to wipe out a minority group in the 21st century, you don't go about it by means of Nazi-style hate rhetoric. Why bother? All you have to do is convince the majority population that your targets have a tragic disability, and hordes of well-meaning people, believing your motives to be purely compassionate, will happily contribute to your campaign for cure or prevention, patting themselves on the back the whole time for being such good charitable citizens.
Where's a genetic cure for bigotry when we need one?