How can gayness have a genetic basis?

[All-In Flynn]

I really hope no gay posters take offence at any of the ideas kicked around below. If you are offended, please accept at least that the offence is unintentional, and don't read too much into any one of them.

I find it difficult to accept that sexuality has a genetic basis, but I see that a lot of people seem to accept it. Has this been established firmly? I remember that experimenters bred fruit flies which appeared to exhibit homosexual behaviour, but I'm not sure that this is definitive. Can someone who does think it's genetic explain why they think this?

The problems as I see them with the genetic theory go like this: If it is genetic, it is 'genome-ubiquitous' (everywhere you go, every culture has at least a knowledge of the concept). To me this implies the gene (or geneplex) is very old - older than the gene for blue eyes, say.

Nothing too controversial so far, I don't think. But then we come to the idea of reproductive fitness. At first glance, homosexuality would appear to be a very definite barrier to successful reproduction. Admittedly, gay people can reproduce, and historically they often have, but this can be argued as a function of the stigma historically attached to gayness and the oppression it has frequently encountered.

It seems pretty clear to me that gayness, while not rendering reproduction impossible, very definitely makes it somewhat less likely. And given the assumption that the gene is very old, does it not seem that less and less 'unfitness' is required for the gene to go extinct? Think of the gene's frequency as 'bankroll', generations as spins of a roulette wheel, and the 'unfitness' of the gene as the 'house edge'... it may take a while, but even the largest bankroll will eventually go broke. And even this is ignoring the difficulty of the gene spreading in the first place... if we presuppose genetic variety, where is the selective pressure to favour gayness? What kind of 'mixed strategy' could incorporate gayness as part of a successful genetic dynasty? I'm unfamiliar with any model save the 'sneaky male' hypothesis outlined briefly by Dawkins, and I'm unconvinced. Does anyone know of a better model?

I'm not satisfied with the argument that says that since gayness is alive and well, it must de facto be evolutionarily fit - this may be so if the genetic basis can be (or is) proven, but as oultined above I can't for the life of me see how.

We can, I think, dismiss recurrent mutation - current estimates vary from 5 - 15% of the population, usually hovering around ten - far too high a frequency, it would surely be unique among such mutations. And yet I've read studies correlating left-handedness with gayness; apparently one is 'ten times more likely' to be gay if left-handed, whatever exactly that figure may mean. Which of course strongly implies that there is a genetic basis...

Could it be a genetic aberration that ironically has survived precisely because of the stigma historically attached to it? (Gays disguising their gayness and thus passing on their gay genes.) Amusing to think that if Falwell and similar monsters really wanted rid of gayness, maybe they should embrace it and hope that it dies out!

The best model I could come up with for gayness having an evolutionary niche was a bit of a Goldberg, involving separate genes for male and female gayness, finding evolutionarily fit phenotypic expression in opposite genders - the gene for male gayness increasing some facet of fitness or other in women, and vice versa for the female gayness gene. The best excuse for this model I could find was the popularly-repeated notion that women are more given to gay behaviour (without necessarily being exclusive lesbians) than males... this I attributed to women lacking a Y chromosome, thus leading the 'lesbic' gene to find 'gay expression' somewhat more frequently than its male counterpart. And I have read of a theory involving genes increasing female fertility to foster gayness in men - but this I'm suspicious of. It seems to just swap the phenotypes across genders, and hey - girly-men! One thing gay men appear to be unanimous on is that they are not 'women with penises' - they are a breed apart. And while this is not strictly evidence against such a theory, I'm uncomfortable with such 'neatness' - the answer feels simple in a way that experience has led me to regard with suspicion.

So basically, after all this thinking and armchair theorising, I can't find a way to see how gayness could be evolutionarily fit, and hence can't quite accept its genetic basis - can anyone offer further insight?

[m_the0ry]

What if being gay happens to be a highly probable mutation for the offspring of the most evolutionarily fit?

[All-In Flynn]

Feels like special pleading to be honest. And if gayness is accepted as an inhibitor of reproduction, in the long term, that brand of evolutionary fitness isn't all that fit. If not, then that could be a plausible model - though I'd be curious as to how.

[vhawk01]

It could also be an unavoidable, rare by-product of something else. Not everything is fit. Do you think Tay-Sachs has a genetic basis?

A better question is, how could it possibly NOT have a genetic basis? I can't think of a single way besides mass global conspiracy spanning thousands of years and various species. That seems pretty unlikely to me.

[Bill Haywood]

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the gene (or geneplex) is very old - older than the gene for blue eyes, say.

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Don't assume that something has to be selected for in order to exist. We can do calculus, even though that obviously was not selected for. Nor would there necessarily be strong negative selective pressure, since critters can both reproduce and have gay sex. Possibly, or rather, likely, some important trait that was selected for has a side effect of sometimes causing same sex attraction.

Birth order effects odds of being gay, suggesting it's not genes per se, but the womb environment, and therefore still of biological origin.

There is not a clear explanation for WHY homosexuality would emerge from genes, but there are strong indications that it does.

If I remember right, identical twins raised apart have a tendency towards having the same sexual orientation.

Oral histories of gays are very telling. Time after time in coming out stories people describe their desperate attempts to be straight, often lasting for decades. For them, it's clearly of biological origin.

Wiki on Penguins: "Male penguin couples have been documented to mate for life, build nests together, and to use a stone as a surrogate egg in nesting and brooding. In 2004, the Central Park Zoo in the United States replaced one male couple's stone with a fertile egg, which the couple then raised as their own offspring."

The Wiki entry has some interesting ideas:

http://en.wikipedia.org/wiki/Homosexuality

[Phil153]

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A better question is, how could it possibly NOT have a genetic basis

[/ QUOTE ]
Do scat and waddle fetishes have a genetic basis? How about strong preferences for the female beauty determined by the prevailing culture? Your ancestors used to like fat chicks.

Much of specific human behavior doesn't have a genetic basis. I'm not talking about general traits, like aggressiveness, intelligence, language ability, reflectiveness, and so on, which are largely the result of brain architecture. I'm talking about being attracted to things which have emotional and cultural significance, such as scat or waddles or beefy males.

[L'ennemi.]

I think Our Omnipotent Lord was well aware of this problem, that's why he told to hate the Gays in the Bible.
This stigmatization forced gays to hide and marry, and have offspring.
This was only the only way to preserve the gayness gene. This plot was vrucial in human evolution, as Gays are betterlooking and much better artists.
Unfortunately, the moral decadence of our society is endangering this plan. What gay haters don't realize, is as was correctedly hinted in OP post, the tolerance for gayness in our societies will eventually lead to the demise of gayness, and consequently of fashion sense.
The future of humanity is bleak. God is punishing us again for our sins.

[tarheeljks]

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Not everything is fit. Do you think Tay-Sachs has a genetic basis?

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basically sums up what i was going to say.

[vhawk01]

[ QUOTE ]
[ QUOTE ]
A better question is, how could it possibly NOT have a genetic basis

[/ QUOTE ]
Do scat and waddle fetishes have a genetic basis? How about strong preferences for the female beauty determined by the prevailing culture? Your ancestors used to like fat chicks.

Much of specific human behavior doesn't have a genetic basis. I'm not talking about general traits, like aggressiveness, intelligence, language ability, reflectiveness, and so on, which are largely the result of brain architecture. I'm talking about being attracted to things which have emotional and cultural significance, such as scat or waddles or beefy males.

[/ QUOTE ]

Being attracted to fat chicks definitely has a genetic basis, at least the type of fat chicks you are talking about.

But homosexuality isn't really a specific human behavior, its more of a general one. I wonder what would happen if we did twin studies on people into scat? Not sure, but the ones we've done on homosexuality show a genetic component. We've had many discussions on these forums about the FITNESS of homosexuality, and I think that is still a controversial topic that I have no strong opinions about. But the genetic basis for it seems pretty hard to argue with.

[Phil153]

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Oral histories of gays are very telling.

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No, not really. Few people can understand and control the basis of their urges, many of which arise from something as simple a childhood experience, or wiring that gets crossed during childhood between affection and sexual attraction toward males. Why do you think it's often stated that males tend to be attracted to people like their mothers? Conditioning. And that's in normal individuals.

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Time after time in coming out stories people describe their desperate attempts to be straight, often lasting for decades. For them, it's clearly of biological origin.

[/ QUOTE ]
By this reasoning, child molesting is also biologically based. Yet you don't hear many people advocating that idea, even though it would be significantly more "evolutionary fit" than gayness.

The fact is that our brains are so advanced, and go through such a long period of haphazard development, that all kinds of things can get screwed up and crossed and confused, regardless of your genes. Putting it down entirely or mostly to genes (which the evidence does not support) is taking away from where the responsibility usually lies - which is with the individual.