Evolutionary roots of homophobia

From The Economist: legality of homosexuality

The Economist this week has a main feature on Gay Rights. Some countries are moving forwards, while others move backwards. The map above, showing where homosexuality is permitted in law (shades of blue-green) and where it is illegal (orange and red), cries out for explanation. It is very far from random.

There is a hint, perhaps, in the language used by red-zone politicians. The Economist writes

"IN THE argot of human rights, LGBT means lesbian, gay, bisexual, transgender—a catch-all term for sexual minorities. But Yahya Jammeh, president of Gambia for 20 years, has a different reading. “As far as I am concerned,” he thundered during a televised speech in February, “LGBT can only stand for leprosy, gonorrhoea, bacteria and tuberculosis.” He compared gay people to vermin, and said his government would fight them as it does malaria-bearing mosquitoes, “if not more aggressively”."

The Economist also notes that:

"Revulsion against homosexuals is ancient, deep and, in its way, sincere."

Why?

Homophobia clearly draws on ancient, powerful emotions - chiefly disgust. Some of us oldies will remembers literary dialogues of the mid-twentieth century, where a refined woman gets to drawl in genuine puzzlement: "But what exactly do homosexuals actually do?"

Sex is inherently a mucky and disease-prone activity; we've all heard of sexually-transmitted diseases. Arguably, certain homosexual practices are more disease-prone. Some people find the whole idea of sexual activity frankly disgusting: homo- or heterosexual. However, any male or female who believes this sufficiently strongly is not going to leave any descendants - so genes coding for that emotional reaction are unlikely to spread widely in the population.

Some small percentage of the population (c. 3-4%) is significantly into homosexual practices. As this kind of sexual activity can't lead to descendants how can such people exist? Greg Cochran thinks the culprit is some kind of infectious agent priming an underlying heritability of 0.3 - 0.4; we know that sexuality is on a hormonal continuum so perhaps LGBT people are simply 'on the spectrum'?

Still, like all practitioners of sex, homosexual people historically engage in a potentially disease-spreading activity. And there is no genetic come-back from disgust in the heterosexual community, as so graphically articulated by Yahya Jammeh, President of Gambia above.

In the West, our standards of hygiene are higher and perhaps we're rather more self-controlled and empathic. We've become 'tolerant' (there's a word!) and of course we should be - LGBT people are what they are - and in the last decades we've agreed not to use the power of the state against them.

But let's not pretend - in some blank slate fashion - that those underlying, ancestral, selected-for emotions have somehow been edited out, because they plainly haven't.

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Sparse pickings on the Internet for this topic. A Scientific American article makes a brave attempt but looks to paedophilia and xenophobia for explanations - disconfirmed both by common sense and the evidence. The whole area is stymied by liberal hand-wringing.

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In case it wasn't obvious, let me summarise the speculative thesis of this post.

The reason for an evolved heterosexual disgust towards homosexuals (mislabelled as 'homophobia') is that in the environment of evolutionary adaptedness (EEA) homosexuals were more likely to be disease vectors.

See also: "The 'is' and 'ought' of homosexuality".