An evolutionary explanation for homosexuality and homophobia

I’m just going to remind everyone that the fact that something is evolutionary selected for does not make it moral or right.  Explanations are not justifications, the naturalistic fallacy is a thing.  I’m exploring this in the spirit of “knowing why an immoral behavior exists makes it easier to extinguish”.  To be super clear: homosexuality is fine, homophobia and gender policing are wrong.  Hat tip to Dario Amodei for the original idea, although I’ve expanded it somewhat.

It’s obvious why homosexuality is an evolutionary puzzle: a drive for non-reproductive sex shouldn’t get very far.  But it’s equally weird that shaming of male homosexuality has been strongly selected for, culturally if not genetically.  Why would you shame someone for not competing with you for a thing you really want?  The correct response is to bring them a drink and skip off to that thing that’s so important to you.  I think I may have an answer to both questions.

Let’s talk about the side blotched lizard.  Male side blotched lizards come in three types.  Orange throated males are high in testosterone and maintain a large territory with multiple females.  They will chase off any competitor they find.  Yellow throated males dodge this by hanging around the outskirts and looking female; when the orange throat moves to a different part of the territory they rush and mate as quickly as possible.  Blue throated males bond with a single female and guard against her mating with a yellow throated male (who they will correctly identify as male because they have more time to devote to the project), but may have their female stolen by an orange throated male.  So the side blotched lizards are in an enormous game of rock paper scissors where orange beats blue beats yellow beats orange.

Side blotched lizards are not the only animal with this mating system.  Males of Paracerceis sculpta (a marine isopod) come in three forms: alpha males that control a harem, beta males that imitate females well enough to stay in the harem (and mate when the alpha isn’t looking) and gamma males, whose strategy can best be described as “be really small and run really fast”.   A very small number of male Ruffs also have a female-imitations strategy.

Genuine female imitation was probably not a viable reproductive strategy in the evolutionarily relevant time period, because most of the people you knew had known you for years.  But what if you could convince the high-status males that you were not a reproductive threat they might leave you alone long enough to sneak in a few matings.  Not as many as the high status men, but more than you could otherwise get while low status.  One way to convince them you’re not a reproductive threat is to convince them you’re sexually interested in men, and the easiest way to do that is to be exclusively interested in sex with men.

Preferring sex that can never produce babies does not sound like a winning offspring-production strategy at first glance, but evolution is weird.  One possibility is that homosexuality is an overshoot of the strategy, but if that were true you’d expect male bisexuality to be much more common than homosexuality, and the reverse is true (currently, in America).  Alternately, evolution could be counting on societal pressure leading gay men to have sex with women occasionally.  You know, like what happens now. Presumably not as much (reproductive) sex as straight men, but some.  The whole concept of a sexual and romantic orientation is kind of new, maybe the biological drives that lead to identifying as gay now led to preferring men but occasionally having sex with women in the past.

If this strategy persisted, evolution would develop countermeasures like, say, aggressive shaming of homosexual attraction and gender non-conforming behavior by men.  You know, like what happens now.  Hell, we have pick up artist culture and r/theredpill describing the problem in these exact terms.*

Some additional evidence: a man’s chance of being gay increases dramatically with the number of male pregnancies his mother carried (doubling as you go from 0 to 3 older brothers).*  There are a lot of possible explanations of this, but one would be to convince older brothers you’re not a threat/avoid putting too many familial eggs in one strategy basket.  The high cost of testosterone on the mother’s body probably also plays a role, but these are not mutually exclusive, it could be a lemons/lemonade situation.

One implication of this would be that homosexuality and gender-non-conforming behavior should be punished less as monogamy takes root, because high status men can’t do better than the single most fertile woman.  In practice, the highest status males can still mate with multiple women, but they lose the social ability to warn other men off them, making them more vulnerable to a sneaker strategy.  Additionally monogamy usually comes up as property and paternity rights become more important, which makes men more paranoid about potential threats to fidelity.  But I’ll acknowledge this is equivocal at best.

This is very far from proven and I can only think of very limited tests for it, but it is way more satisfying than the “cultures afraid to rock the boat” explanation.

*Forgetting that that piece is misandrist as hell and doesn’t seem to distinguish women from furniture, I’m annoyed by his math.  To make it work either the world is completely overrun with gamma and sigma males, or the average man has 2-3x as much sex as the average man.  Please get back to me when you’ve normalized (in the mathematical sense) your sexism.

*This is a reminder to stop using “genetic” when you mean “biologically determined” or “unchangeable”.

2 thoughts on “An evolutionary explanation for homosexuality and homophobia

  1. I’m a bit confused as to how a deception with no chance of success could be threatening–and if homosexuality only existed as a deception, how could anyone believe it? If half of apparent homosexuals were helpful uncles or something and the other half were ‘pretending’ to be that so they could have affairs, that might make sense.

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