Matt McIrvin made an interesting comment at Pandagon:
If the DNA is a magical encoding of the complete human, instead of the genetic input to a process that has a lot of other inputs and eventually results in the human, then it’s a short leap to concluding that the rights of the baby inhere in the DNA the moment it’s all together in one place.
He was talking about abortion, but the false notion he mentions there has implications in a number of issues, particularly having to do with essentialism.
The first example that came to my mind was the so-called gay gene. Various ways in which homosexuals apparently tend to differ from
normals heterosexuals are pored over and excitedly touted as pointers to The True Nature of homosexuality, and there's the eternal fight between the people who say it's inborn and the epsilons who say it's a choice people make for no better reason than sheer contrariness.
Why I don't buy it after the jump.
Now, from what little I know about the topic, I gather sexual orientation is neurochemical in nature, like depression or artistic ability, and results from a combination of genetic and environmental influences. Of course, the same could probably be said for things that are choices by anyone's definition. When I decide whether to walk 15 blocks or take the subway, it's a choice, to be sure, but it's a result of predilections and preferences regarding walking in various weather conditions, exertion, and convenience -- both how I define it1 and how important it is to me. All of those preferences are neurochemical, and all of them result from a combination of, e.g., genes optimized for shlepping around the savannah and the fact that it may be 20 degrees F outside.
McIrvin's point, however, is that genes don't make the person. Your DNA isn't a microcosm of who you are, and so it's erroneous to talk about a "gene for sexual orientation" (much less a "gene for homosexuality" like that has any more of a causedness about it than heterosexuality). Genetics, then, is just another influence.
I'm oversimplifying here; I think it's clear that sex, for example, is almost entirely genetic rather than environmental. Skin color varies over a very wide range based on genetics and a very, very narrow one due to nutrition, sun exposure, and such. But a person's genes are only a very, very basic outline of who they are, no more predictive -- and in some cases probably far less -- than educational background, or parents' socioeconomic class.
And the idea of a "gay gene" is not really any truer, ultimately, than that of "gay rebellion." Nor necessarily less dangerous.
1The subway requires me to go slightly out of my way, and climb stairs and wander around in ways I don't have to do if I walk, but it saves me the walk.