Homosexuality is a 19th century western construct. In modern non Western socities, you have people who openly partake in same sex relationship s but will deny they are homosexuals till they are blue in the face.
Which is quite challenging in identifying historic gay people. Both Alexander and Edward II were gay under modern definitions but both married and had children as well as bastards from politically unimportant heterosexual affairs.
And of course situational sexualiy is well attested.
The true model for the process of human evolution (read Jared Diamond’s The World Until Yesterday) would be the small village or clan, a collection of extended families. To what extent would such a social structure tolerate single persons of either sex? To what extent are they capable of such support? What are the odds two gay persons of the same gender and roughly same age would occur in a group of 20 to 100 individuals?
I was thinking of the native North American model (which is shown in IIRC “A Man Called Horse” or “Little Big Man”) but that was the gay male role. There was no apparent corresponding female role. Again just a WAG, but unlike modern society, there was no job and money to go out and buy Doc Martens; there were tasks to do to survive - there was hunting (male role) there was food preparation, gathering of plants, making clothing, etc. Society usually did not have a role for someone who did not want to pair up, and there was less incentive for the extended family to support someone who didn’t “play the game” so to speak. (And in one of the movies I mention above, there is also the scene where when the old woman’s husband dies, the rest of the tribe takes the couple’s possessions and pushes her out in the cold to die.) Of course, male domination goes a long way too - we see plenty of societies where women basically have little to no say in their marriage arrangements.
When someone suggests to me that homosexuality is a “choice” (WTF?) I point out that nobody told me what I wanted or liked, that my deep heterosexual desires were in no way taught. I grew up before sexual material was widely available to the curious youngster, and did not get a lot of exposure to such - yet I know what I like. To me, this seems to show that such desires are very instinctual, on the level of the instinctive behaviour programmed into many other species. Meanwhile, we do have the instinctive recognition of other humans (and other animals) in non-sexual ways; we can tell pretty or handsome from not, and most people agree what constitutes “good-looking”. We can tell young from old, we can tell “cute” and “repulsive” deep in our gut, and so on. (A lot of women especially, I’ve seen, have a very strong response to snakes… and nothing to do with bible stories) To me, this suggests deep instinctive programming, not learned responses.
If you don’t think coding this desire seems like a more simple task than coding a liver, that’s fine with me. It’s just a thought. Insects and such seem to be able to do it, while being significantly less complex than us.
The thing about this is that the in utero conditions are also heritable, just on the mother. So we then have to explain why genes are inherited that cause a specific environment in the uterus.
Why would genes be the only reason something is heritable? That’s a big leap.
That ignores epigenetics entirely, for starters.
ETA: Seems like this is a point that’s been made already in this thread - reducing all heritability strictly to genetics is questionable. Actually, we know it’s not true. There are other “nature” elements beyond strict genetics that don’t cross over into “nurture” territory.
In “genetic/evolutionary” discussions, what kind of conclusions can be made about the ultimate steady-state percentage of putative genetic material among the population given that a lesser percentage express it phenotypically?
It’s a possibility. I guess the question is, to what extent are these traits inborn like straight or gay? To what extent are they “learned” behaviour from being abused themselves?
The biggest sex organ in the human body is the brain. It’s complex enough that it’s very difficult to figure out what is going on at any time. There are plenty of non-sexual quirks and obsessions the human brain is capable of too. At this point it’s important to separate sexual pleasure from social dominance. There’s the old saw, for example, that rape is more about power and dominance. To some extent, he same would likely apply to S&M and pedophilia (where pedophilia activity is a learned experience, the perpetrators acting out after experiencing abuse themselves). It’s possible, though, that perhaps some forms of pedophilia are miswiring of the brain. S&M, similarly, seems to be attaching pain to sexual activity (either giving or receiving).
I’ve never made a study of what causes this sort of behaviour. I’m going to make the guess, however, that more superficial obsessions - liking red lingerie, for example - is learned behaviour while more basic desires - liking large breasts, perhaps - is more instinctive.
But, if certain results are accidents of fetal development, then it’s entirely likely that factors like birth order, etc. can influence whether these accidents happen. My guess would explain why the “problem” happens. Evolution has taken programmed instinctual behaviour and adapted it to work in a very pliable, flexible brain. To correct this would require a radical redesign of the brain. maybe when we’re all forgotten and dust, intelligent cockroaches will evolve that don’t have gay offspring. So far, our brain works “good enough” and that’s all Nature aims for.
Not the only reason, but they are an important factor, and this is mainstream genetics. For the purposes of this thread, let’s assume that evolution can act on heritable traits.
Ok, then that leaves the door open that there are not necessarily specific genes that create those certain conditions in the uterus or that such genes are not common across most, if not all, humans. That there’s an epigenetic explanation for those uterus conditions which are correlated with homosexuality.
Even so, does it matter? Humans are pretty darned successful at breeding. Rather than looking for a reason why homosexuality is selected for, there’s no reason, at current rates of expression, any biologically driven (whether purely genetic, epigenetic, or whatever) conditions favoring homosexuality should be selected against. That may be different if it was expressed in 95% of the population, but it’s not.
Heck, even if it was expressed in 95% of the population, all you’d need is for enough women to look for enough “sperm donors” for the number of children they want. You couldn’t have a low-tech monogamous solution… but how many humans have ever been truly monogamous anyway?
Given all the complex mating behaviors in nature, this would be a pretty simple one to solve. It’s not like we’re one of those solitary species that has to travel a thousand miles to meet at a particular full moon on a particular beach… and yet even those guys manage to reproduce.
That last line reminded me indirectly that in many species, most “guys” (males) do *not *manage to reproduce. (Most “gals” do.) Since the sustainability of a population depends mostly on female fertility, this might hint that it’s not that crucial for Mother Nature to prevent male homosexuality. (Note too that most surveys tend to find lesbianism less common than male homosexuality.)