Schizophrenia is the price we pay for minds poised near the edge of a cliff

Genetics is messy - as I understand it most genes don't code for a single thing, so assuming evolution is "selecting for schizophrenia" that only implies that there is an evolutionary benefit to some of the things controlled by the same gene(s) that control schizophrenia, that outweighs the disadvantage of schizophrenia.

Homosexuality is interesting from this perspective too - common enough that evolution has to be selecting for it, yet basically fatal to reproduction, so what are the benefits that evolution is selecting for? Is it advantageous to groups, or maybe the same genes confer an individual benefit to non-homosexuals?

I always wondered if it was natures check on overpopulation. I know that is controversial to say, but it seems most fitting on its face

My best guess it that there is a societal/group benefit in reducing aggression (maybe not unrelated to they way our closest DNA match, Bonobos, function).

I don't think we're at the point yet, and certainly not in last few million years of evolution, where overpopulation is an issue, and since evolution is all about (collectively) creating the largest next-generation population, this isn't the way I would expect to see increased competition for resources to play out.

For evolution to “select” for homosexuality, wouldn’t it have to be hereditary in large part? As far as I can tell, to the extent that theres any evidence for that the effect of genes on sexuality is kinda limited

> Homosexuality is interesting from this perspective too - common enough that evolution has to be selecting for it,

Are we sure this is the case? I think it's more like homosexuality isn't extremely selected against on a population level. Evolution doesn't really select for, more like evolution is a process in which least-viable-specimens are killed off for their environments. It could very well be that a small number of homosexual specimens are simply irrelevant to evolutionary fitness.

Male vs female differences, including differences in typical sex-specific sexual attraction, are obviously genetic, even if we've yet to figure out all the specifics (where are the male's "curve detector" genes, etc).

Do men and women both have the coding for male/female attraction, with one typically disabled ? This perhaps seems most likely, in same way both sexes have nipples, etc. Without knowing exactly how this all works we can only speculate how male/female genes can combine to create same-sex attraction. Obviously it's not so simple as inheriting a gay gene from one of your parents!

> Male vs female differences, including differences in typical sex-specific sexual attraction, are obviously genetic

Typical is putting in a lot of work in that sentence. I could rephrase it with the same truth content and make it much more ambiguous.

"Many phenotypical sexual differences in humans are obviously genetic. Some very common differences in sex-specific sexual attraction are likely genetic as well. For large swaths of sexual attraction, we have absolutely no evidence of a genetic link."

What's funny is that the one example you facetiously picked (a curve detector) is extremely culturally dependent. Trying to tie elements of human sexuality to evolutionary just so stories is usually pseudoscience. When we start isolating genes for the things that we think of as natural, if we ever do, I bet you $100 the mapping from our social experience of these traits to some kind genetic reality is muddled to the point of total detachment.

The article's first paragraph has some alternative factors in selection

> Traditional evolutionary hypotheses, such as those invoking kin selection, mutation-selection balance, and evolutionary mismatch don’t quite explain this.

There's lots of explanations here but one that is often mentioned is "kin selection". If you increase evolutionary fitness of nephews, nieces, etc. There's many others, some of which apply here and others which don't.

> What's funny is that the one example you facetiously picked (a curve detector) is extremely culturally dependent.

Actually, it wasn't intended as facetious! I'd bet money that male attraction to females is indeed based on curve and jiggle detectors! If not this, then what - it has to be based on some (simple, perceptual) physical characteristics. I realize that female ideals vary a lot between cultures, and time periods, but the differences are more about things like fat percentage and distribution than the underlying characteristics that visibly differentiate men from women.

> Some very common differences in sex-specific sexual attraction are likely genetic as well. For large swaths of sexual attraction, we have absolutely no evidence of a genetic link

Sure - it seems there may be a large degree of imprinting as well, but homosexuality does seem to be an important special case given that it typically means lack of descendants. Of course evolution is really about sub-populations and gene-pools, not individuals, and it seems there has to be some benefit at that level otherwise this trait would have been out-competed in the population.

Do rural populations have lower rates of homosexuals as a % of offspring? How would nature "know" we are overpopulated and bias towards homosexuals?

> but homosexuality does seem to be an important special case given that it typically means lack of descendants

For much of human history, that has been false. In many societies, there has been strong pressure to (heterosexually) marry, arranged marriages - with the result that most individuals with a homosexual orientation end up participating in heterosexual reproduction-so homosexuality is much less of an evolutionary disadvantage than you’d assume.

Modern Western society puts great emphasis on marrying for love, marrying on the basis of actual attraction rather than social pressure or political calculation, being “true to yourself” - and in such a society, a homosexual orientation does significantly reduce the odds of participation in classical heterosexual reproduction. But modern Western society isn’t normal in world-historical terms, what we consider “normal” is actually rather novel