Wednesday, February 23, 2005

Gay Genes: What the future might hold

Via Dissect the Left, I came across a very interesting interview with evolutionary biologist Greg Cochran. Cochrane presents a pretty plausible argument that gay genes will never be found because the more likely cause is that male homosexuality is caused by a virus. See also here. Here are the highlights:

Isn't it the current expectation among scientists that we will eventually find some sort of "gay gene" that codes for homosexuality?

... we can be pretty sure that there is no gene that codes for male homosexuality: not one that accounts for much of the story, anyhow. Although there is some familial clustering, there is certainly not a simple Mendelian gene: there is no simple Mendelian inheritance pattern of the type we see in cystic fibrosis or muscular dystrophy. In fact, identical twins are usually discordant for homosexuality (~75% of the time) - so homosexuality is unlikely even in a homosexual's twin. Obviously some environmental effect plays a big role. ...

What makes a virus an especially likely candidate as a cause for homosexuality?

Well, the general idea is that while evolution makes human genes that reduce reproductive success rare - and it does, usually - various kinds of parasites are entirely capable of causing syndromes that reduce fitness and are much more common...

Male homosexuality reduces reproduction a lot: it's around at the few-percent level, and seems to have been around for millennia. I could say the same thing about a number of other syndromes that we've already figured out and the cause was an infectious organism in about 90% of the solved cases. It's the way to bet. If it were new, I'd consider drug side effects and such, but it's a lot older than that.

A virus is most likely, rather than a bacterium like TB, a protozoa like malaria, or a parasitic worm like dracunculiasis. If it were caused by a bacterium we'd probably already have prevented homosexuality by accident with antibiotics, and a worm we'd have seen. ... Is there reaction against considering this theory from within the scientific establishment?

Some. Prominent evolutionary biologists mostly think it makes sense and might be true: Bill Hamilton thought so. Trivers thinks it makes sense, Randy Thornhill does, Paul Ewald does, James Crow does. Alan Grafen, a pupil of Richard Dawkins, came up with a similar idea but thought that, if true, it should be kept forever secret, being an utter sniveling coward.

Working on an idea like this is bad for a biologist's career. You could never, ever get any NIH funding. If you proved it, I expect that the Nobel committee would drag you to Stockholm in chains and take your money.
This story raises so many questions it's hard to know where to begin. I should point out that this idea seems to have respectable names behind it. Dawkins, Trivers and Hamilton are well known names and if they think the theory is good, with the math to back it up, then I'm inclined to listen. It's a shame that work like this would be shunned. This is the result of modernity's attempt to build ethics on science alone; scientific research becomes hijacked by political considerations. If the theory is true and if a cure can be found, there will be a ferocious debate about whether or not it should be allowed. It strikes me as a very similar issue to the cochlear implant for deafness, which some oppose on the grounds that it attacks deaf culture. I'm not sure the case to deny would be solid. I doubt very much that if this theory is ever proven, that it would account for all gays (in the interview Cochran mentions that it may not apply to lesbians because their behavioral distribution is different). So, gay culture would survive. If the theory is true, what does that do to the SSM debate? (which will likely have quieted down some by then) Does it do anything? I'm not sure the law would change. There'd still be gays around, after all. It would, however, take away a great deal of the impact "gay gene" thinking has today. "They were born that way, just like being born black... blah blah blah." You know what I think of the merits of that - it's a false parallel and racist to boot, implying that one's race determines one's behavior. As always, I look forward to hearing what others have to say.

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