Sexual selection can’t explain the homosexuality that’s been documented in over 400 species of animals. So, in the world of these animals, this means that homosexuality is a normal way of life, right?
The idea that an animal can be “effeminate”-- a human social construct-- is highly dubious.
If by “effeminate” you mean a male animal is more like a female of the species biologically or behaviorally, that still seems to have nothing to do with animal homosexuality, unless the animal is, you know, homosexual. Basically I don’t see what effeminacy has to do with the question.
As a former Ph.D. student in the neuroscience of sexual differentiation, I have learned how to dumb down this talk as well as anyone. I am about to attempt to improve on my record.
Most people think that we develop as a boy or a girl because of the chromosomes we get. We get XX (girl or (XY) boy and then we become that sex. In fact, genetics do not directly determine the sex anyone becomes. That is the realm of the sex hormones and they are the ones that determine the genitalia, breast development, facial hair, brain sex, and almost everything else that makes a man an man and a woman a woman. The role of genetics in this process is to form the proper sex gonads that go on to kick off the processes later but it doesn’t always work exactly as expected.
The brain and body pass through a series of “critical periods” during development. These are windows in which the presence or absence of given sex hormones during that time determines if the body and brain develop in a male or female orientation. Genetics is mostly out of the picture at this point and not all of the critical periods have to go in the same direction.
It is very possible for there to be glitches in some parts of this development and the individual develops characteristics opposite their genetic sex. It is easy to induce these things in the lab and it happens frequently in nature as well across many species. There isn’t much genetic or evolutionary about it. It is just a developmental curiosity that tends to happen a lot. Atypical critical periods during brain differentiation can easilly explain how homosexuality develops in general and why it isn’t really subject to much of the speculation brought up in questions like these.
Shagnasty, while I’ve got you here…
Does anyone know if any of these “critical periods” are in the later 2/3 of the human pregnancy? I’m wondering (and this is just total off the top of my head wondering, nothing educated about it) if micropreemie babies may miss out on some critical hormonal piece in the mother’s uterus that may make them more prone to gender - uh - flexibility, than full term babies. Perhaps our saving babies born too early has increased or will increase the number of genderindeterminate or genderqueer adults we’re seeing, and it’s not merely cultural acceptance that makes it seem as though there are more “different” folks than in our grandparents’ days.
Of course, I’ve gone on record as saying I don’t give a rat’s ass if gender OR sexual preference is biological or not. As long as everything is consentual, I don’t care if it’s because God made you that way, a chromosome got doubled, or you read all about transsexuals and decided to try it out. The motivation means nothing to me.
But I am still curious.
Indeed. Having it alleged to be biological never kept TPTB from locking up the “mentally ill”, did it? Folks who like to hate, discriminate, lock folks up, deny folks rights, etc, don’t need a consistent excuse, just an excuse.
It’s important to differentiate between homosexuality in the human sense (ie, being gay) and homosexual acts. A male can have sex with another male or use sex as a dominance display without being a homosexual. Human homosexuality is tightly linked with our ability to form pair-bonds (you could call it “falling in love”), which is quite unusual in the animal world (except maybe in birds). So, I question that homosexuality (in the human sesnse) has been observed in 400 species of animals.
I am not sure but it is an interesting question and it certainly can’t be ruled out. The details of this science aren’t all that well worked out yet especially in humans (the anti-human experimentation problems bite us yet again on this one).
Most people seem to use “genetic” and “biologically determined” interchangeably when they are not in this case. The critical period phenomena hasn’t seemed to hit mass consciousness yet like other scientific explanations that people tend to latch on to and use in everyday theorizing of their own which is strange because it seems obvious and intuitive to me. It could have all kinds of subtle and not so subtle implications that will make perfect sense when they are put into mainstream textbooks in a few years.
And the other thing is, organisms vary. For lots of different reasons. Some of those reasons are genetic, but not all of them. But suppose you have a genetic trait that reduces the expression of secondary sexual charactistics. Well, most of the time you’re going to be preferentially selected against. The chicks go for the macho males, and you’re out of luck.
Interestingly, some species have males that sometimes impersonate females. The “alpha” males don’t recognize the mimics as males and therefore their male-male competitive behaviors (whatever those might be for that species, for instance attacking other males until they flee) aren’t triggered. And the gender mimics can therefore mate with the females unmolested.
However, this probably isn’t the reason for most non gender stereotyped behavior in animals, as Shagnasty explained it’s more likely there’s been some sort of developmental error and those animals are just less likely to breed than those that have typical behavior.
As for how these errors can be tolerated, well, evolution typically works on “good enough” rather than perfect. If you have a mechanism that works 99% of the time improving it to work 99.9% of the time is pretty unlikely. As long as you produce plenty of offspring, the fact that 99% of them get eaten in their first week of life doesn’t matter much. Life is very wasteful, most organisms die before they have the chance to breed. Wild animals with injuries or congential defects are not exactly rare, even if they are much less likely to breed successfully than healthy animals.
The other thing is we know for a fact that homosexuality isn’t “genetic” the way most people use the term. We know things like eye color or blood type are under genetic control, but the simple example of identical twins shows us that homosexuality cannot be something simple like a “gay gene”, because in cases where one identical twin identifies as gay there’s only a 50% chance the other identical twin will identify as gay. If there were a gay gene, it would be more like 99%, if one twin has blue eyes you can be sure the other twin will too.
And also note that “homosexual behavior” doesn’t mean much. Suppose we have a male who mounts other males and tries to mate with them. That’s homosexual behavior. But it isn’t much like human homosexuality if that male also tries to mount females as well. Put it this way, there are mechanisms in the animals brain that tell it “attempt to mate with this thing in front of you”. One type of error would be if the animal attempts to mate with an object or animal that is not a receptive female. Another type of error would be if the animal doesn’t try to mate with a receptive female. The first error is not very serious, but the second type is very serious. So there’s a lot of selective pressure to try to fuck anything that moves, not so much to refrain.
Interesting interpretation, and I don’t disagree.
What I usually mean when I say it is that it’s irrelevant because we should accept “Because I felt like it!” as a valid reason as long as it’s not hurting anyone. There needn’t be a better reason than that.
“Excusing” homosexuality, or transsexuals, or polyamorous folks, or the mentally ill or people into bondage/scat/paraphillia or black or whites or stupid people because “they were born that way - look animals do it, so it must be part of nature!” means that I shouldn’t excuse them if they *choose *to be that way. It’s saying that this behavior is bad and I ought to be outraged by it and stop it, but I’m excused from doing so if it’s biologically based. It’s still wrong and bad and disgusting, but “they” have no control over it, so I’ll pity them instead.
I say screw that! “It” is all good and valid and wonderful, as long as it’s consentual. It is NOT bad-but-the-will-of-God, it’s GOOD! It’s all good, as long as no one’s getting hurt.
Bipolar but don’t want treatment? Fine, as long as you’re not a danger to others.
Like to masturbate in stiletto heels while wearing a brasiere made out of cottage cheese? Go for it!
Like being scourged by your same-sex partner while whistling show tunes? Have at it, as long as he’s willing to scourge you and hear “Defying Gravity” for the 800th time.
Like a single opposite gendered monogamous life-partner in only the missionary position once a week? Find a like-minded parter and have a happy life.
You’re a woman who wants to wear blue jeans and be an engineer? Shit, no one’s going to look twice. Have a nice life!
You’re a man who wants to wear Donna Karen and be a nanny? Why should this be any different from the above?
Shagnasty, thanks for the answer.
If it is polygenetic then it would have a 50% correspondence rate. Or, it could have some other genetic cause which is “turned on” in the parents and then passed to the children. Just because it isn’t 100% doesn’t mean that it’s not genetic.
Homosexual activity and homosexual pair bonding has been observed in the animal kingdom in many different species. Check out the book by Bruce Bagemihl if you want details.
As for why it stays around it could be a method of population reduction, a genetic mutation that is advantageous in the heterozygous condition, or a genuine advantage. For example, there are some species that use homosexual sex as a means to reproduce. Whiptail lizards of the american southwest desert are all female and they have sex with each other, taking turns being top. Lizards that are “dommed” are more likely to give birth to fertile eggs than lizards that do not have sex. If males were ever to reappear, the lesbian sex would probably remain for a while.
But suppose it were polygenetic, identical twins have the exact same genes. Blood type is polygenetic, but if one twin is AB-, or whatever, the other twin is guaranteed to be AB- as well. So if there are five genes controlling this and you need allele Q, allele U, allele E, allele E and allele R to turn gay, well, identical twins should have all the same alleles, except for a random couple of mutations out of 9 billion base pairs. So 99% of identical twins would share sexual identification.
And there’s no way any gene can persist as a method of population reduction. As in, a gene that says if it’s too crowded, turn gay and stop reproducing. This makes no sense, how can such a gene be selected for? A gene that tells you not to pass your genes on to the next generation doesn’t get passed on to the next generation.
Anyway, it isn’t that clear that homosexuals have significantly lower reproductive rates compared to straights anyway. And even if we found that gays today have fewer children, would that have been the case 500 years ago or 50,000 years ago? Homosexuality is sometimes viewed as equivalent to sterility, but we know from anecdotal evidence that plenty of gays have kids.
That’s not how genetics works. Have you ever examined “identical” twins? Most of them are not identifical at all. I have two uncles who vary in size and weight yet are identical twins. The idea of genes switching on or off and that is all of your inherited existance may have been believed a long time ago but that is no longer believed now. Skin colon, eye color, height are all polygenetic. Like “single” gene factors, polygenetic factors are influenced by the environment. Because of the environment influence, there are inherited characteristics that can be caused by genetics yet not identical in identical twins. Take schizophrenia for example. We know that it runs in families, even those where the children are raised seperately from their parents. However, when it comes to identical twins, it is not absolute that they both will have it. Therefore, it has been established that it is polygenetic. There are many, many other things that are inherited this way, but I just woke up so I can only remember schizophrenia because we talked about it in genetics class when discussing this subject.
And of course there are ways genes can persist as a method of population control. Have you ever heard of Tay-Sachs? This is an inherited disease that kills the child by 2 or 3 years old. You might wonder how the gene can persist despite killing the child but that it is because it conveys an advantage in the heterozygous condition. Let’s say you have a mom that carries a mutation that make it likely for her offspring to become gay. THis makes her very fertile and she produces more kids than other women. Some studies suggest that the aunts of gay men are more fertile compared to other women so it’s not like this is a completely pulled out of a hat. Furthermore, let’s say that this certain mutation causes her to be more likely produce gay children in times of stress.
Mom A produces a gay kid and 2 het kids that go on to pop out babies.
Mom B produces 3 het kids all of whom go on to pop out babies.
In times of stress when food production is low, the family of mom B would suffer from greater malnutrition than Mom A’s family. Thus, the mutation survives.
But anyway, I don’t believe that we need the stress argument to account for all gays. The whiptail lizards don’t seem to suffer from stress and homosexuality constantly pops up in the animal kingdoms in environments that appear to be rich. It may be one factor, but it is hardly the only one.
Many cultures accepted gays and did not force them to have kids. In fact, for most of human existance, we lived in hunter-gatherer tribes that are forced to adopt strict methods of population control. Infanticide is quite common, in fact, IIRC correctly, if a !Kung woman gives birth to twins, she kills both rather than trying to pick which one she will keep. A gay uncle or aunt might mean the survival for both of those twins.
Here are some more that are thought to result from polygenetics: ADHD, Tourette’s Syndrome,, Parkinson’s, Alzheimers and others.
Here is the cite for the “homosexuality means fertility for female relatives” thing: They found that both the mothers and maternal aunts of the homosexuals were significantly more fertile than those of the straight men.
And I haven’t even talked about epigenetics either. 
Do you have a sort of a cite for this claim?
I said IIRC which means “If I Recall Correctly” I studied the !Kung and other tribe in 2000 and don’t have any of the texts from that class at my current location. Apparently, I was wrong about the !Kung killing both twins, I confused it with another tribe. Here is a page on twin infanticide in general. This paper mentions twin infanticides in other groups but not the !Kung although they mention general infanticide practices of the !Kung.
There certainly seems to be some genetic component involved in homosexuality. In identical (monozygotic) twins, it was more common for both to be homosexual than in fraternal twins. From here:
However, as has been noted, the correlation is not perfect; for almost half of homosexual identical twins, their twin was not homosexual. Clearly there is not a single determining gene involved. There is evidentally a developmental/environmental component involved too.
There is no reason to suppose that homosexuality always has the same basic cause. Human sexually is a highly complex behavior; any number of factors, both genetic and developmental, can influence it. As an analogy, consider dwarfism. Small stature can be due to a wide variety of genetic causes, as well as developmental ones such as malnutrition or disease during childhood. It is pointless looking for a general “cause” of dwarfism. There may also be no general “cause” of homosexuality.
Although some homosexuals do have children, as long as they have fewer than heterosexuals do the trait could be selected against. And exclusive homosexuality amounts to behavioral sterility; as such it could in theory be strongly selected against.
Despite this, there are any number of reasons homosexuality could persist in a population. First and foremost is that those cases due to developmental factors rather than genetics would not be subject to selection. Since in these cases the trait is not heritable, it cannot be eliminated by selection. Secondly, if the trait is due to polygenetic factors coming together in a certain combination, it may be difficult to select against it, especially if the individual factors have positive effects when they are present separately.
Some evolutionary theorists believe that the rate of homosexuality is sufficiently high in humans that it demands factors such as kin selection to explain it. Although the rate of homosexuality in the US population has often been cited as 10%, the rate of *exclusive * male sexuality is, according to recent studies, substantially less, perhaps 2-4%. This is not much higher than the rate of sterility due to physical causes, which may be around 1%. Kin selection arguments have not been advanced to explain these other causes of sterility; nor to explain other types of behavioral sterility, such as celibacy for religious reasons, asexuality (which may be as common as homosexuality, but has been subject to almost no study), and extreme nerdiness. In other words, homosexuality may not be common enough in the population to demand some special evolutionary explanation.
You haven’t met our cat, Kelly. If Kelly were a human, he wouldn’t just be gay, he’d be – and I say this with zero disrespect indended – a flaming drag queen.
I’m talking over the top stereotypical. He’s the biggest drag queen cat I’ve seen in my life. Gives my wife and me endless hours of amusement.
PS - the wife named him, before she knew me. Thought it was a cool Irish name. I think it backfired on her.
Now, back to your educational and fascinating discussion.
It’s called sarcasm. I know that in reality animals don’t act like the opposite sex. I was just using that word to get my point across.
Roughly 10% of gay men have biological children, and roughly 25% of gay women have biological children. Don’t ask me for cites, it’s late.