Homosexuality and natural selection

In my post on the taste of meat I briefly mentioned the problem of homosexuality and natural selection. That is to say, why does homosexuality persist, given you think natural selection would weed it out because gay men are not having babies and therefore not propagating their genes.

Many people have taken this to mean that homosexuality is some kind of defect, where something has gone wrong because the ultimate goal in life is making babies and these people aren’t doing it.

Luckily, Rich had written a talk to explain all about it. Having first delivered it at Rationalist Week 2009 he also delivered it to Leeds Skeptics later that year.

I’ll skip the interesting, but never the less skippable introduction and get straight to the answer.

Genes do different things based on their environment. So in one person with one set of genes, a specific gene may do one thing – but take that gene out and put it in someone else with a different set of genes and it may well do something else.

This is what we find with the so-called gay gene. In men, it is more likely to make them homosexuals. But put that same gene in a woman and it actually makes them more fertile. Therefore a woman carrying the gay gene is more likely to have children and even though some of them may turn out to be homosexual men, the women will continue to propagate the gene because of their increased fertility.

There are other factors at work as well of course – homosexuality is a combination of both nature and nurture. Having the gay gene doesn’t mean you will be gay – it just increases your chances. But that is Rich’s argument as far as the genetic side goes.



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This entry was posted on Tuesday, November 15th, 2011 at 12:28 pm and is filed under Religion & Politics, Science. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.