Firstly, who cares? I’m not asking if it’s a “lifestyle choice”. I understand that people are born gay. Even if a person did “choose” to be gay later on, more power to them. It’s not a moral question.
That aside, why do people postulate that such a thing might exist? It seems to me, gay or straight, roughly 50% of any persons ancestors will have a preference for male partners and 50% for female. Presumably, we inherit a whole complex set of genes for finding other humans attractive. Surely you have to learn what you find appealing? We can’t be born with an internal picture of what a sexy person looks like, can we?
There must be a mechanism for assigning the reproductively viable sexual orientation with biological sex. Maybe the evolutionary cost of making this mechanism perfect, is greater than the cost of the occasional non-reproductive individual. Maybe it is impossible to make it perfect.
If like Miranda in The Tempest, you were ‘biologically straight’ but didn’t encounter a member of the opposite sex until adulthood, would you instantly find them attractive?
We’re curious monkeys - trying to understand how things work is what we do. People looking for genetic factors in sexuality are doing the same sort of thing as people looking for genetic factors in, say, left-handedness, or indeed, not that different from people engaging in any other kind of research.
But also: not everyone is as open-minded as you are about whether it matters if a choice or whether it’s constrained - and for these people, the answer to genetic question is quite important to their position.
Dunno - but the question you just asked is only determined by research, including research into genetic vs cultural vs other factors. So it turns out: you do care about the answer.
We’re animals - and I think it must certainly be true that animals have some sort of built-in image of what a mate is - blackbirds don’t need to learn that other blackbirds are more attractive than squirrels, or lamp posts - it’s instinctive.
This is a somewhat self-contradictory paragraph, and I certainly disagree with parts of it.
We are likely wired to not only notice sexual dimorphism, but some aspects of what constitutes fitness. While it’s popular in some circles to imagine such things are entirely dictated by society, that doesn’t make any evolutionary sense. Why even have sexuality if it’s going to be left entirely open what organisms we wish to copulate with?
But, as alluded in my previous post, being wired to find blemish-free skin attractive, say, does not mean there are specific genes for such things.
Fwiw, I’m open to the idea it could be a slightly different chemical balance acting on relevant areas of the brain, that balance being delicate at the best of times.
The moral question is definitely separate from the biological root cause question though.
Because in the context of biology, “Is it OK to be gay?” is the same kind of question as “Is it OK to wear polyester?” or “does vanilla go with cinnamon?” - Mother Nature does not have a relevant opinion on the topic.
Humans do a whole bunch of things that they’re not ‘supposed’ to do. It’s interesting and maybe useful to know why things are the way they are, but there’s not a direct link from there to some platonic notion of ‘how they oughta be’.
Don’t get stuck in the nature vs nurture debate. Sexuality is almost certainly a little bit of both. And don’t get stuck on the idea that nature = genetic. Twin studies tell us that being gay is partly genetic and partly not. But it may also be partly due to conditions in the womb rather than, or in addition to, genetics.
We are biologically “programmed” be acquire language, but children not exposed to language before a certain age have difficulty mastering it later in life (from the limited data we have on the subject). The same may be true about sexuality, and so Miranda might not have a normal reaction to a sexual partner, but because the genetic/environmental background she had was out of sync, rather than there being one all-encompassing cause.
BTW, you might want to do some searching on this MB because this subject has been covered many, many times.
Also, don’t buy into the notion that if it’s “nature” that will make it “OK” with everyone who would otherwise be a homophobic bigoted asshole. Racists have tended to believe more firmly than biologists that race is all a matter of biological difference but that hasn’t kept them from being racist assholes.
The legality of homosexuality is a separate issue from the whole nature vs nurture thing anyway. In a society that recognizes individual rights, behaviors that do not harm other people should not be outlawed, regardless of whether they are “natural” or not. And that doesn’t even touch on the point that “natural” is an absurd classification in the first place.
More precisely, that hardwiring is presumably governed by genetics at some level, but in an extremely complicated way. There’s no one gene you could switch off that says “prefer blemishes/prefer lack of blemishes”. Rather, there are probably a whole host of genes that interact in many subtle ways that lead to that result, and changing any one of those genes, or any set of them, will result in many other changes as well, many of them seemingly unrelated.
As for the causes, we’ve learned a lot from twin and sibling studies. Identical twins have a greater correlation in their sexuality than fraternal twins, and biological siblings have a greater correlation than adopted siblings: These both imply that there’s some genetic component. Biological siblings raised together have a greater correlation than biological siblings raised separately, and adopted siblings have a greater correlation than completely unrelated people: These both imply that there’s some component from upbringing. Fraternal twins have a higher correlation than siblings born separately: This implies that there’s some component from the uterine environment. And yet, even among identical twins raised together, the correlation still isn’t perfect, which implies that there’s something other than genetics, the uterine environment, or upbringing that’s relevant, too.
My personal theory is that there is a genetic basis for a predisposition to be gay, but that environmental factors (particularly in utero) play into it as well. This would go a long way toward explaining the higher incidence in second or third sons.
Genes tend not to last unless they confer some survival advantage, my belief it that the survival advantage here is that gays are “supposed” to be spare parents. In the event that mom and dad fall off a cliff or are eaten by sabre toothed tigers, having a gay uncle with no children of his own to provide for could be the difference between life and death.
I didn’t express it well. I’d been debating the topic over drinks when I wrote it and was more than a little bit drunk.
I certainly don’t think it’s determined by society, but there must be an element of that. I’m pretty sure I was born straight, but if I’d been raised exclusively in the company of men, I find it plausible that I’d have developed an attraction to them instead. If I saw a woman for the first time at 20, I don’t know if it would really be a light bulb moment. I’d probably just think she was a kinda weird looking guy.
I think what I was driving at, was that there’s no need to suppose a seperate gay gene. “Gay genes” in a man, would be “straight genes” in his mother/sister/daughter and vice versa. I’ve heard serious biologists trying to work out what the evolutionary survival value of a gay gene might be, and I don’t see that there has to be any. We might all have genes for both preferences and, for example, conditions in the womb might determine which are expressed.
I’m not sure its so much a gene but I think they can do dna testing on an infant and say from that if the child would have a bigger chance at certain things like being gay or left handed.
You are missing the mechanism whereby genetic differences are constantly being introduced (and re-introduced) in individual organisms. They may not be passed on, but they may occur again.
Unlikely. There are much easier ways to have “spare parents” around, if there is a survival advantage for such. Just make a certain number of people sterile. Which, btw, happens quite a bit. Also, one would expect more lesbians than gay men since women do most of the child rearing. Besides, are there any human societies where orphans are commonly adopted by “gay uncles”?
And genes don’t have to confer a survival advantage to “last”. That’s a common misunderstanding about genetics. It’s enough that they don’t confer some survival disadvantage.
Yes, it would be “easier” to have more sterile people than to have some percentage of the population be gay. But that implies a deliberative aspect to evolution that plans out evolutionary changes and can select for the most efficient solution. Which, of course, is not how evolution works. If having a certain percentage of the population be homosexual provides a survival advantage, then the mutation that led to that will be propagated, even if there’s an easier possible solution - or even if there’s an easier extant solution.
I suspect the number of women in pre-historic societies that had any real reproductive choice was pretty limited. A man who’s not interested in having sex with women, is probably not going to have much sex with women. A woman who’s not interested in sex with men… is probably still going to have a significant amount of sex with men, regardless of what she wants.
3a) We’re talking about how homosexuality could have evolved in humans, so we’re talking about arrangements in human populations across hundreds of thousands of years - and possibly earlier, since any potential “gay gene” does not necessarily have to originated in humans. So the existence of any society with a wide-spread practice of adoption by gay uncles is irrelevant – any human society for which we have any sort of reliable record is much too recent to have had any impact on the over-all evolution of the modern human animal.
3b) That being said, I believe it’s been pretty common in most societies throughout history for orphans to be adopted by uncles (when available), gay or otherwise. All else being equal, an orphan who doesn’t have to compete for resources with his cousins is going to be at an advantage over an orphan who does.
3c) The “gay uncle” hypothesis is not specifically about raising orphans, but about the ratio of contributing adults to mouths that need to be fed. The children in a hunter-gatherer group that consists of, say, two breeding pairs, and two non-breeding homosexual pairs are going to have a survival advantage over the children in a hunter-gatherer group that consists of four breeding pairs, simply based on allocation of resources.
I’m open to correction on this point, but my understanding is that genes aren’t passed because they provide a survival advantage to the individual, but because they provide a reproductive advantage to the group. A genetic mutation that makes you twice as likely to develop cancer before thirty, but makes you ten times as fertile, is going to get passed on, even though it drastically reduces the organisms ability to survive.
This is significant to this conversation, because a possible “gay gene” is not going to have any impact on an individual’s survivability, but is going to have an obvious impact on their ability to pass on their genetics. The “gay uncle” hypothesis offers an explanation for why homosexuality, which should lead to the individual being outbred by heterosexuals, still provides a sufficient reproductive advantage to the group to prevent it from being selected against.
Which isn’t to say that the hypothesis might not still be completely wrong. But if it is, it’s not for any of the reasons you suggest.