Pardon me while I gag. But more importantly, this is off-topic. The question is about heterosexuality, not homosexuality.
Unless your claim is that we only have sex as differing-gender couples because angels came down and told us how to do it? No, wait! A snake told us to. Ergo, heterosexuality is as demonic as homosexuality. So, all sex is bad. Ergo, God wanted our species to die out, so that lemurs could take over the earth in our stead.
It all makes sense now! :rolleyes:
I agree with this, but I believe it was Richard Dawkins who pointed out that homosexual men sometimes have excellent access to fertile women.
It seems to me much more likely that the answer will be more like “why do men have nipples?”
The structures in the human brain that cause sexual arousal are likely to be broadly similar in males and females. What causes an undifferentiated early embryo brain to develop into a male brain that is sexually attracted to females, or a female brain that is sexually attracted to males? It’s likely that a lot of these things are both present in the male brain and the female brain, it’s just that some are developed and expressed in the male brain and not developed in the female brain, and vice versa. Just like males have nipples, but never get the hormonal cues to develop swollen breasts or produce milk. But if you give a male synthetic female hormones, his breasts will start to swell, and he’ll start developing female secondary sexual characteristics. And vice versa.
Male rats given estrogen exhibit female mating behavior, female rats given testosterone exhibit male mating behavior. But that doesn’t happen with humans. If you give a gay man testosterone it doesn’t make him attracted to women, and if you give a straight woman testosterone it doesn’t make her attracted to women either, and vice versa for estrogen. A gay guy on testosterone is a butch gay guy, not a straight guy.
The point is, there are some mechanisms in the human brain that regulate sexual attraction, and we know these are shared up until adulthood in a rat brain and that rats can have their mating behavior changed simply by giving them sex hormones. Humans aren’t like that, but it seems pretty likely that somewhere during development these behaviors get built, although we don’t know when or how or what exactly, and at one point that embryonic or fetal brain isn’t gendered and at a later point it is. And if things develop one way that brain will end up attracted to males, and if it goes another way that brain will end up attracted to females, or maybe both or neither.
And that doesn’t mean it was advantageous for some people to end up gay, it just means that it happens, and perhaps that the extreme plasticity of the human brain is advantageous, and that sometimes things go wrong, but that’s a consequence of having a gigantic overdeveloped brain.
The other thing to consider is that while homosexuality probably isn’t some purposeful adaptation that benefits the extended kin group, or some such, it isn’t as deleterious to reproductive fitness as some people think. Gays and lesbians often have children, it’s not exactly unknown. A gay guy isn’t doomed to be the nurturing uncle that increases his inclusive fitness by caring for his straight sibling’s children, gay guys often have their own kids. I don’t know if anyone has done a study comparing the average number of children of gays vs straights, but that study wouldn’t show gays with no kids and straights with lots, there are plenty of straights with no kids too.
And we have to consider the effects of homosexuality on fitness, not in America today, but rather in the setting where human sexual behavior evolved…in small hunter-gatherer bands. It’s not obvious to me that a male hunter-gatherer who prefers to have sex with other males is doomed never to have offspring of his own.
You’re referring to the fable on the origin of love, as told by the character of Aristophanes (as opposed to the actual historical person of the same name) in Plato’s dialogue The Symposium.
As others have alluded to, this is actually a pretty good question. Lots of ink has been spilled talking about it. As always, I’d recommend The Red Queen: Sex and the Evolution of Human Nature. There’s a decent overview of the thrust of the main point of the book here.
You can sit down and ask that question about a lot of human behaviors. I’m guessing the answer to “why” is extremely boring and incomprehensible to anyone but a specialist. It’s all about those trillions and trillions of connections…
I remember reading about a study (yeah, that’s how the lying always starts) where heterosexual men would look at different types of curves. A certain part of their brain would light up much more strongly than in women or homosexual men. This area of the brain would also become strongly active when looking at naked women. So there are circuits in our brain dedicated to judging whether we’d hit it. Which makes sense…
I wonder if that holds true for homosexual women as well.
Ah, but it is fairly uncontrovertial to say that infertility is the result of an error in development, and an aberration from (and frequently not preferable to) the biological norm.
I would like to propose that as usual, you don’t know what you are talking about and have nothing of any value to contribute to the discussion.
Oh, and now you can forgive me, since you love all your enemies.
You said you read them “over and over and over.” Doesn’t sound like scanning to me.
Psst! Ixnay about the akeovertay!
Actually, I was suggesting that you not read those threads as an alternative to complaining about them, not as a supplement.
Considering how badly you misunderstood my post, which consisted of a single, short sentence, it would probably be wise not to put too much stock in your ability to extract a valid conclusion from a longer piece based on a brief scan.
The idea that homosexuality is cause by demons is completely asinine.
Everyone knows that it’s really caused by fairies.
Fairies with toasters.
Regards,
Shodan
Damn you, I try so hard not to laugh out loud at work. I just had to explain what made me laugh so loud.
Having too narrow a definition for what is found sexually attractive could hurt a species. If all humans were only attracted to members of the opposite sex who had all the proper secondary sexual characteristics of their gender and none of the opposite, it would be beneficial in an environment where perfect mates of the opposite sex were abundant as it would prevent them from spending reproductive energies on mates they could not produce progeny with, but it could present problems when they were put in a situation where the only mates available did not fit the criteria for “Obvious sexually mature female/male”. If women were only attracted to large healthy males with a masculine upper body, facial hair, and a deep voice, if there was a situation where most of the males were wiped out and the only ones left were immature or effeminate, there would be no reproducing going on. Obviously, there are women with very specific tastes, but they are just a portion of the female population. Some women find effeminate men attractive, or boys who have not fully reached sexual maturity, and they pass on their genes because in the past it made it easier for them to reproduce. Only wanting to have sex with healthy males who look like men from the population you grew up around isn’t very beneficial as humans are a pretty diverse group. Because we are diverse, it’s good to have a diverse range of features that are found attractive.
In the long run, it’s better to have a population that will fuck pretty much anything of the same species, even if about 10% of that population finds itself exclusively attracted to those they have no hope of having young with. People who find inanimate objects or animals sexually attractive are a very small minority as that trait is not beneficial at all.
Debateable. There’s the theory that the majority of sex among humans is for social purposes, not reproductive ones, and that we’ve evolved for that to be so. Note that humans have a permanent sex drive, no obvious signs of fertility, and a low fertility; we appear to be made to have sex fairly often, without the women getting pregnant right away.
I’m reminded of the syndrome ( don’t recall the name ) where the body of a pregnant woman will produce a surge of testosterone at a particular time of the pregnancy, and the result with a girl child is “tomboyism” or whatever you want to call it. A girl who likes stereotypical male things and has no interest in sterotypical female things. And then there’s studies showing that transgendered people have areas of the brain that belong to the opposite sex of the rest of the body, no doubt leading to their discomfort. And studies showing that parts of homosexual’s brains appear similar to the opposite sex’s version.
This sort of thing has given me a few thoughts on this subject :
1 : Homosexuality appears to be only one example of a larger issue; sometimes one or more areas of the brain end up with the opposite sexualization of the body.
2 : While it may or may not be a defect in animals, in most cases in humans, it’s not. A human doesn’t need to be heterosexual to produce offspring because he/she can simply decide to do what’s necessary survive and/or have children, regardless of their attraction to the opposite sex or tastes in recreation. Just as a woman lacking a maternal instinct would generally care for children she’s in charge of instead of abandoning or eating them, or a man not interested in hunting is perfectly capable of providing for himself and any family. Humans are not nearly as dependent on instinct as animals, so a fatal defect in an animal is just a personality quirk or even an advantage in a human.
3 : Thanks to # 2 above, I wouldn’t be surprised if there are more homosexual humans than in other species. It simply doesn’t matter in humans as much.
4 : As you mention, humans are a highly social, cooperative species, and just because an individual is homosexual doesn’t mean he/she isn’t contributing to the survival of his/her relatives, which works just fine in Darwinian terms.
I’m incidentally reminded of one of my favourite Futurama throwaway jokes about a $1.99 Sex Shoppe named “The Beast With Two Bucks.”
Carry on.
I would like to say that I also find this idea silly - but I recognise you are trying to be helpful from your particular point of view, so my only problem is with your assumed certainty.
Well yeah, the evolutionary origins and “reasons” for heterosexuality have been somewhat studied. I think the more important question is why more people don’t think about the cause of heterosexuality. That is, not why it first came about, but how and and in what manner individual organisms become heterosexual. The cause for homosexuality should follow naturally from our eventual understanding of what causes heterosexuality. In the cases of lower species, what causes identification of and attraction towards opposite sex, and nonattraction to the same sex, and how strong are these, and what are the exceptions (some animals for example, use sex not just for procreation but also for social bonding, with either gender). In the case of humans and some other higher intelligence animals, what other things factor into the equation (socialization, learned behavior, culture, etc.)
My first lab rotation was in a neuroendrocrinology lab, and we studied the effects of estrogen and progesterone on very specific structures in rat brains and how they led to sexual behavior. There is a decent-sized literature on sexual dimorphism in the brain and its effects (answering part, but not all, of your question), but it would take me a while to dig up relevent and interesting cites. (I am doing my thesis in a development-oriented lab, so I barely remember what I did during my rotation. I can take a look though, if you’d like.)
Not really. More likely it’s a feedback mechanism with both traits reinforcing the other. Or, a chicken and egg deal-- which came first, the harem structure or the sexual dimorphism?
I don’t know that that type of social group is most common among mammals, especially since most mammals are either rodents or bats. And it’s not very typical of primates, either, which is what we are. If we were “typical” mammals, we’d have sex lives like rats and mice.
So is homosexuality. But then, “the norm” for behavior is a social construct anyway, so where does that get us?