Bugs and rainbows

This blog post is an account of an exchange I had with a friend of mine on the topic of sexual orientation and gay germ theory, translated and lightly edited. If you’re already familiar with the the main thesis, it will not contain anything new, but I believe it is a decent overview.

I like this topic because of its shock value: the position itself is utterly reasonable, but it elicits a very strong emotional response in people. On a personal level, I do not care very much about people’s preferences. I believe it is a good thing that gay people are allowed to participate in society productively. Our existing laws and social norms, if correctly enforced, would suffice to limit the spread of a hypothetical pathogen. Considering that they have historically been targeted with violence and quite brutal hormonal treatments, it is fine to have some special provisions to protect them. (I am not endorsing hate speech laws)

I should also say that I do not have complete confidence in this, although I believe it is likely to be true.

Here goes :

Homosexuality was initially classified as a disorder, then was gradually removed from the DSM under pressure from activists. This is therefore not an example of the excessive medicalization of recent decades but an example of political interference in the scientific domain. I know there’s a whole body of work that rationalizes politicizing the scientific, academic, and medical worlds, which is a different conversation.

I take this opportunity to say that I am using the word “disorder” because “disease” is too morally connoted. You could see it as a euphemism (because it really is the same thing for our purposes) or as an effort to remain neutral.

I will also clarify my position on one point: we can discuss classification all day, in the end the question is that of which criterion to use to define a disorder or a disease. The only consistent definition is the Darwinist one: a condition is dysfunctional if it is systematically an obstacle to reproduction or survival. The brain is (among other things) a reproductive organ. If it systematically targets partners the individual cannot reproduce with, it is obviously a reproductive disorder. However, my position is much worse than that: I think it is very likely that male homosexuality is caused by a pathogen, analogous to what toxoplasma gondii does in the brain of a mouse (changing fear/attraction reactions to spread at the expense of the host).

Male homosexuality is a mystery, but not because it is weird. The spectrum of human sexuality contains much more bizarre, and much more individually/collectively harmful, things. There are people out there having sexy time with octogenarians, sheep or corpses. Male homosexuality is a mystery because it is common and (usually) exclusive. Other alternative sexualities are much less frequent (a small fraction of one percent) while male homosexuality remains constant over time, between 2 and 5% of men according to various estimates.

The separation between sex and reproduction is relevant in the modern context. It is not relevant in the historical context, before reliable contraception. Heterosexual sex was causal towards reproduction. Behavior that goes against this instinct could not maintain itself at a high level in the population, because the reproductive cost would have been far too high.

Typically 80%, even in the modern environment. This graph comes from Emil Kierkegaard’s post on the same subject.

However, the condition can remain common if a pathogen co-evolves in tandem with our immune defenses: smallpox, for example, has maintained a case fatality rate of ~30% for several millennia, despite immunity building up in the affected populations. As people became more resilient, the virus in turn became more virulent. Gay germ theory explains an apparent evolutionary paradox as a matter of course.

Many other lines of reasoning are possible, although everything is circumstantial.

• Unlike most forms of discrimination, homophobia is not based on tribalism but on disgust, which is an instinct usually reserved for pathogen vectors. It is also innate: we teach people not to be homophobic, not the other way around. Amusingly, homophobia is more heritable than homosexuality.
• Not all cultures develop an aversion to homosexuality, but many do, which could be explained as convergent cultural selection.
• Isolated tribes either have a rate similar to that of our societies, or 0 cases and no notion of what it is.
• In animals, only two species have exclusive homosexuality at a strangely high rate: sheep and humans. Biologists often confuse demonstrations of dominance (mounting) as well as cooperation between females in the absence of paternal investment, for animal homosexuality.
• One thing that is fairly controversial nowadays is the historical (but also modern) link between homosexuality and pedophilia or ephebophilia. Spring-autumn relationships are very frequent, sometimes even customary (from ancient Greece to Rimbaud). 30-50% of pedophile victims are young boys, while almost all pedophiles are men. This is a strong over-representation in relation to the number of homosexuals in the population. This is consistent if we consider the hypothesis of a parasite that must find new hosts. I am not, of course, saying that most gay people are pedophiles, but the rate is anomalously high.
• Anal sex is an excellent vector of pathogens, and homosexuals are a bit like nature’s test tubes in that regard. In recent history, we have had epidemics that spread much better among homosexuals than heterosexuals. For example, monkeypox and AIDS. Very unlikely to be the only means of transmission, but possibly one among others.

Look up “sacculina” for an established, analogous case in a different species.

There is also a possibility that homosexuality has evolved, and is therefore a strategy rather than a disorder. Many such hypotheses have been put forward, each more far-fetched than the last. They do not survive two minutes of inquiry.

• “Gay uncle theory” proposes that the investment in his nieces and nephews compensates for the non-reproduction of the uncle. Problem #1: it would select for the heterosexual phenotype at the expense of the homosexual phenotype. Problem #2: this assumes an investment at least double the parental investment, which is ridiculous and never happens in practice.
• “Sneaky Fucker Theory” proposes that homosexuality is actually a feint to stay in camp and have sex with women while straight guys are… out hunting? Problem: it’s not a feint at all, gay guys almost all have an exclusive attraction to the same sex.
• Sexually antagonistic selection sometimes causes a disadvantage in terms of fertility for men to be compensated by an advantage for their female relatives. This does not bear out in practice. If it were, the effect should be very visible.

These explanations are very naive but taken seriously and frequently put forward, including by the scientific community. A pathogen is prima facie a lot more likely. This pattern should alert us to the fact that this path ends in a mental stop sign for most people.

The most important point is of course that homosexuality is barely hereditary at all as a trait, and therefore probably not of genetic origin. Personality traits converge strongly between identical twins, but while the homosexuality of one of the two introduces a strong divergence, the other is usually not gay. Such differences between homozygotes are normally only observed in the event of an accident or major “shock”. Something “shocked” the gay twin.

Female homosexuality is both less common, and more rarely exclusive, so I think if there’s a cause, it’s probably distinct.

The Pragmatopian has a more speculative piece on the same topic: Saccharine Psycho-Virus. Beware, it gets weird!