Homophobia is Heritable, too

If homosexuality is learned, it's wrong, but if homophobia isn't, it's right?

Encyclopedia Brittanica defines homophobia as the “culturally produced fear of or prejudice against homosexuals that sometimes manifests itself in legal restrictions or, in extreme cases, bullying or even violence against homosexuals (sometimes called ‘gay bashing’).” This intrigues me because it resembles Wikipedia’s tendentious definition of acquired homosexuality, which was the inspiration for Bryan Caplan’s article.

It reads:

Acquired homosexuality is the discredited idea that homosexuality can be spread, either through sexual "seduction" or "recruitment" by homosexuals or through exposure to media depictions.

Implicitly, the reasoning seems to be that in order for homosexuality to be free from moral criticism, it must be innate, but in order for homophobia to deserve it, it must be learned. A serviceable rule of thumb: if you’re on the political left, then there are two—and only two—group differences which not only may be, but must be a result of genetics: one’s gender identity and sexual orientation.

The psychology of male homophobia probably goes back to evolution in the following way: appearing to be gay when you aren't is a huge liability from the standpoint of reproduction, and seeming chummy with gay people makes one appear to be gay. Also, making exaggerated displays of revulsion toward gay people is a way to signal that one is very much not gay.

Men face greater competition for mates than do women—more men die without a partner than do women, and the average man is considered less sexually desirable by the average woman than vice versa.* This is because women pay a higher cost for reproducing: they must expensively gestate a fetus within their bodies and risk death in childbirth, whereas a man can simply impregnate her and disappear, never to face the repercussions. In the evolutionary economy, sperm is cheap and plentiful, eggs and uteruses are priceless. As a result, we should expect that the offer a man must make to a woman to convince her to have sex with him is more extravagant than what a woman must offer a man. (Supporting this prediction, Clarke & Hatfeld found that 75% of men accepted an unsolicited offer of sex with a random woman, while none of the women did.)

The hypothesis that homophobia is a biological adaptation makes verifiable predictions:

1) Homophobia will be heritable; genetically identical twins reared apart will be more homophobic than fraternal twins reared apart, and adoptive children will be more homophobic than their adoptive siblings and parents if their biological families are more homophobic. Using data from 4,688 twins, Verwej et al. (2008) report that:

Genetic modelling showed that variation in homophobia scores could be explained by additive genetic (36%), shared environmental (18%) and unique environmental factors (46%). However, corrections based on previous findings show that the shared environmental estimate may be almost entirely accounted for as extra additive genetic variance arising from assortative mating for homophobic attitudes. The results suggest that variation in attitudes toward homosexuality is substantially inherited, and that social environmental influences are relatively minor.

2) Men will be more homophobic than women because men face greater sexual competition than women and have a greater incentive to deflect an undesirable reputation. From the same article:

Results show that, in accordance with literature, males have significantly more negative attitudes toward homosexuality than females and non-heterosexuals are less homophobic than heterosexuals.

3) Homophobia will spontaneously manifest itself in the absence of counter-conditioning, and it will be culturally ubiquitous, appearing independently in pre-Christian tribal societies. Wikipedia is of strange help here:

In a 1976 study, Gwen Broude and Sarah Greene compared attitudes towards and frequency of homosexuality in the ethnographic studies available in the Standard cross-cultural sample. They found that out of 42 communities: homosexuality was accepted or ignored in 9; 5 communities had no concept of homosexuality; 11 considered it undesirable but did not set punishments, and 17 strongly disapproved and punished. Of 70 communities, homosexuality was reported to be absent or rare in frequency in 41, and present or not uncommon in 29.

How tolerant of homosexuality was Ancient Greece? Less than you may have thought:

During these times, homosexuality was seen as normal and necessary…. Yet, when two men of similar age shared a similar relationship, it was deemed taboo and, in fact, perverse.

4) Homophobia will cause homosexuals to reproduce more often—more tolerant societies will have a lower homosexual fertility rate. This is because evolution will endow parents with a desire to see their kids have kids.

In the 1920s, gay men had to pair up with women and raise families to keep up appearances, even if they maintained a sexual double life shrouded in secrecy. I would guess that the fertility of gay people has declined since then as our society has become more tolerant, but I am having trouble finding time-series data on the fertility rates of homosexuals. But for what it’s worth, this survey found that only 8.1% of gay couples from 2014-2016 were raising children, as opposed to about 40% of heterosexual couples. I would guess that most of those men are raising adoptive rather than biological children sired by surrogacy.

Anticipated objections:

“Women find gay sexy too.”

Do you think women are equally sexually attracted to men they know to be gay as they are to men they know to be straight? There is evidence that women tend to find more masculine men attractive, and that homosexual men tend to be more effeminate (probably because homosexuality has something to do with the activational effects of hormonal signaling during puberty). Moreover, there's evidence that people in general are more attracted to people they consider prospective sexual partners and who they think are interested in them sexually.

*The sexual marketplace isn’t harder on men across the entire age span. Retirement homes are full of widowed women, and if any men end up there, they're very popular.

In a Pew Research study the disparity in singleness by sex is significant, but it does depend on the point in the life span. This doesn't discount the evolutionary reasoning, though, because women have a longer life expectancy and post-menopausal women are incapable of reproducing. The expected result still holds: fertile men are much more single than fertile women because there is more competition for fertile women than for fertile men.

Homosexuality is adaptive (otherwise, how would it have persisted for so long?), so we shouldn’t expect homophobia to be adaptive. From a Darwinian perspective, it should therefore be a matter of indifference whether one is seen as gay by their peer group.

You're missing my point that appearing to be gay when you aren't is a huge evolutionary disadvantage even if actually being a homosexual is advantageous. So, even if the genes for homosexuality promote female fertility to a degree that offsets the loss in reproduction among males who bear those genes, men who don't have them face a huge incentive to not be misidentified by their sexual peer group as a gay person, and to exhibit the masculine qualities that women tend to find attractive.

I should also note that evolutionary explanation of homosexuality is a huge controversy in the scientific literature. Some think it is a modern phenomenon because there is little of it in primitive societies (that is, men who exclusively partner with other men), a result of epigenetic effects—modern gay genes may express themselves with gay results only in our unique environment, which is a far cry from our ancestral evolutionary situation.

The kin-selection theory has been disconfirmed by recent evidence because gay men do not invest differently in their biological offspring (assuming they have them) than do heterosexual men, and there is vanishing evidence to recommend the proposal that homosexuality is a clandestine reproductive strategy, whereby gay men use their homosexuality as a foot-in-the-door for female companionship which will result in offspring.

(Indeed, this latter hypothesis hardly seems like an explanation of homosexuality at all, because it seems to presuppose that gay men lack exclusive sexual interest in men, the very fact it was intended to explain.)

Gay men have a lower rate of reproduction in modern societies, but the female relatives of gay men enjoy an advantage, suggesting that the genes which cause homosexual orientation in men cause greater fertility in women. That effect could be strong enough to offset the harms to men, but again, the evidence is mixed and the jury is widely considered to be out on the question. (I refer you to David Buss's enlightening discussion of the evidence in his terrific textbook Evolutionary Psychology: A New Approach, Ch 5, P 147.)