You May Well Be Born Gay (Or Straight) But Not Everyone Is

Several friends have posted a link to an article titled “No One Is Born Gay (or Straight): Here Are Five Reasons Why“, apparently impressed by what it had to say. I’ve written some short comments on why I think it is badly flawed, and that got enough interest that I thought I would write something more extensive, albeit probably a bit belated.

In the article E Jane Ward takes aim at the gay rights activists who argue that sexuality is innate and therefore society should not discriminate against it, since people can’t help being “born this way”. She’s right that this argument often gets taken too far, such as the example she quotes when Cythia Nixon was told off for saying she had chosen to be a lesbian. But Ward’s argument is really the flip side of the one she is attacking. Some people say they were born with their sexuality, and demand that the same be true of everyone else. Ward thinks her sexuality is a product of environmental factors and her own choices, and insists this must be true of everyone else.1 Neither side allows for human diversity.

The positions not only fail basic logic, they misrepresent the latest science on the issue. I think what the science is revealing is not only far more interesting than either of these approaches, but more liberating as well.

Ward takes aim at some fairly dodgy popular representations of science associating sexuality with exposure to hormones in the womb, as measured by finger length. On the other hand, she entirely ignores multiple pieces of research that indicate a genetic influence on male sexuality. It’s true that these have generally been badly misreported with headlines about “gay genes” burying the subtlety of what has been learned. However, that’s no reason to ignore the actual research.

What seems to be emerging from several different tests is that genes matter for at least male sexuality, but it’s more complex than a “gay gene” in three ways.

1) The correlation isn’t perfect. You can have the “gay gene” and identify as straight or vice versa, but the chances are significantly skewed

2) Sexuality seems to be influenced not by a single gene but by a patch of the genome that is often transmitted together.

3) The best bit: It’s not one but two patches, on entirely separate chromosomes.

Genetics isn’t my strong suit, but unless I am badly mistaken these two patches are entirely independent. Having one has no influence on your chances of having another.

Let’s call the versions of these patches that are associated with identifying as gay G1 and G2, and the other versions S1 and S2

If you’re a cis man and your genome is S1S2 you’ll almost certainly identify as straight. If it’s G1G2 version you’ll probably identify as gay. And if you have one of each…well here is where it really gets interesting.

A giant bisexual flat on an outing at Melbourne's Pride March

A giant bisexual flag on an outing at Melbourne’s Pride March

Should your code be G1S2 or S1G2 the chances you will identify as gay fall somewhere in the middle. But as far as I know, this is all based on studies where men either tell the researchers they are gay or straight. Those who consider themselves bi, pan or whose sexuality has changed with time have been excluded from at least some of these studies, maybe all, as just too tricky to worry about. Which is fine as a starting point, but something that really needs to be addressed as research in the area advances.

I don’t know that the S1G2/G1S2 men are more likely to have fluid sexuality than those with a double up. But would anyone be surprised?

Isn’t it rather likely that all those gay men who say “I was born this way” really were, because their two patches happened to align? Meanwhile others had one of each, giving more room for their sexuality to be shifted by other things, including things that may change with time.

Of course it’s not as simple as G1G2=gay, S1S2=Straight and G1S2/S1G2=bi. If it was there would be a lot more men identifying as bi. Sexuality is a spectrum and there are a lot of people who fall near, but not at the edge, they have some attraction to both men and women, but they’re not equally strong. A combination of circumstances and preferences leads some to take up the bi identity, but many others happily go through life identifying as gay or straight.

I haven’t seen any reliable numbers on the frequency in the population of these two patches, but back of the envelope calculations suggest we’re probably looking at about each patch occurring about one seventh of the time. In which case, around three quarters of men have S1S2 genes, about 2% are G1G2, and around a quarter have one of each.

Ward says that sexuality cannot be genetic because there were lots more gay men in ancient Greece, where it was not only socially acceptable but desirable and our genes could not have changed that fast. But I don’t think there is any evidence that most men of the time were having sex with other men – just lots more than openly do today. The crude model I have suggested could encompass that perfectly well.

Still Not Determinative

I imagine that if Ward bothers to read this piece she will argue that not all G1G2 men identify as gay. This is indeed true. We’re increasingly finding that almost nothing is pure nature or 100% nurture. But even if, for example, 20% of G1G2 men end up preferring women in bed, that shouldn’t overshadow the genetic influence.

For one thing, there could be other genes out there that have additional, more subtle influences.  The ratio of hormones in the womb, the basis of the claims Ward rightly attacks, probably also plays a part, albeit much more subtle than is frequently claimed. And there is almost certainly some effect from what happens to us as we grow up.

Nevertheless, if the combination of genes and environment in utero means you’ve got a 90% chance of eventually identifying as gay as you come down the birth canal then I think saying you were “born this way” is a pretty legitimate call. It’s like saying you were born to be tall – sure exceptional circumstances may prevent it, but those things determined before birth were still more important.

What About The Women?

One of the things that has puzzled scientists and the general public alike since the first announcement of a “gay gene” has been how such genetics could survive. When she first heard about the idea a friend scoffed, “Yes and they’ve found the gene for celibacy too”. Various possibilities have been raised, for example the hypothesis that gay uncles are good for one’s survival chances.

However, leading geneticist Professor Jenny Groves has pointed out that this involves looking at the data all wrong. There is no gay gene, she says. Instead we have genes for sexual attraction to men. There is evidence that women who have these genes are not only no more likely to be lesbians than anyone else, they’re actually particularly fond of getting it on with men. The research is still a bit preliminary, and therefor not conclusive, but it appears that women who have either G1 or G2, or both start having sex with men earlier and have more of it, possibly because they enjoy it more.

These days, with access to advanced contraception, that may have no effect on the birth rate. Indeed it may be that if they like sex that much these women are even less inclined to spend years too tired to do much of it. For most of human evolution, however, such a genetic combination was likely to result in women who had it having more children, easily explaining its continuation in the population even if the men who inherited it had fewer.

Put this way, these “gay genes” could just be an accidental by-product of genetics whose main function was to make women more keen on sex with men. The sound you can hear is gasps of horror from both homophobic bigots and lesbian separatists.

There is one thing Ward and Graves seem to agree on however, which is that male and female sexuality are mirror images. Graves seems to think we haven’t found the lesbian genes because less work has been done researching female sexuality. Ward dismisses the idea that women have more fluid sexuality than men saying, “where have I seen that idea before?  Ah yes, heterosexual pornography.”

They could both be right of course. Certainly, female sexuality has been neglected for research compared to that of men, so it is quite possible there are Sapphic genes out there that, as Graves seems to expect, make men particularly strongly attracted to women.

On the other hand, it’s also just possible that there is no lesbian gene. Or, that there are several. Imagine, just for a moment, if there were three independent genes that encouraged attraction to women and each occurred about one eighth of the time. In that case two thirds of the population would have none of them. Roughly 33% would have one or two, and 0.3% would have all three. If this is true, and remember I am just speculating here, only a tiny number of women would be “born lesbian”. On the other hand, there would be a larger number of women than men born with a some genetic push each way. Depending on a range of factors and experience this could lead them to identify as straight, lesbian or bi. Or to change their identity several times in their life. Which might be where identities like queer come in handy.

I’m not saying the last paragraph is true. It’s entirely possible that the fact that more women identify as bi than men has to do with patriarchal messages that posit female bisexuality as a turn-on for the male gaze, while male bisexuality is denied or condemned. I just think we shouldn’t be too quick to assume this is the only explanation.

What are the implications of all this politically? Well, let’s start with the fact that it doesn’t matter what the cause is, love is love and should be treated the same. If there is legal recognition for marriage, it absolutely must be recognized for any consenting individuals.

On top of that, well maybe we should all just be a bit nicer to each other. The woman who heckled the bi contingent at Melbourne’s Pride March to “get off the fence” might consider that this isn’t as natural a manoeuvre for some as others. Of course that is true even if I am completely wrong and there is no genetic component to sexuality.

But if we start to realise that it is not just that your sexuality might be different from mine, but the causes of your sexuality might be different from mine we might make some progress on acceptance, or at least tolerance. One of us might have a genetic combination that pretty much meant our sexual identity was set from birth, while the other might have been totally up in the air until we encountered the love of our lives at 20 and forever after chased after people who resembled him/her. Each has its own aspects can can make life tough in a society that tries hard to squelch minorities. Let’s start with solidarity, rather than judgement.

From a progressive political viewpoint, this seems to me to allow us a rare example of having our cake and eating it to. One the one hand, evidence that some people’s sexuality is innate makes it much easier to argue against discrimination. On the other hand, those people who don’t want to feel bound by their DNA don’t have to be (at least unless they decide to collapse the wavefunction by getting their genome sequenced).

Super Nerdy Addenda

Pretty obviously, I’ve restricted this discussion to people whose gender identity aligns with their genetics. I’m not meaning to be exclusionary of trans people, I just wanted this to be a blog post, not a book. I doubt we have any data on how the genetics of someone with a Y chromosome who identifies as a women shapes their sexual attraction. Given how much easier this sort of research is becoming, we probably will soon. When we do I’ll be happy to write about it, but until then the possibilities are so vast and numerous I think this post is long enough (although if anyone has links to thoughtful articles I’ll happily add them).

There is however, one additional complexity I didn’t want to include in the main article for length, but thought I would add for those who want to geek out about it.

One of the male gay patches is on the eighth chromosome and therefore exactly the same in men as women. Consequently the whole, “makes women into het sex” idea is straightforward (although even if this idea is right, we don’t actually know if this predisposes these women to be particularly straight, or just increases enthusiasm for sex in general).

However, the original “gay gene” I’m calling G1 lies on the X chromosome. So while men only have one version, be it G1 or G2, women have two. I don’t think we know anything about its recessives or dominance.

The whole idea of dominant/recessive genes turns out to be a bit more complex than the Mendelian simplicity we were taught at high school, but that is a level of nerdy I am not going to go near. So let’s stick to Mendelian thinking for today.

If the male-attraction version is recessive then it wouldn’t affect women much at all. Most women would have at least one S1 version, and this would dominate. So as far as the X-chromosome patch goes the whole idea of male homosexuality being a by-product of genes to make women have more sex would go out of the window.

On the other hand, if S1 is dominant then almost twice as many women as men would be influenced by it. That’s a substantial portion of the female population who would have a gene that strongly inclined them towards attraction to men, and pre-contraception made them more likely to have children.

One more point. For simplicity’s sake I have treated the two patches as equivalent in effect. But we don’t know that. It’s possible one is a stronger predictor than the other, providing a more powerful push. It’s also possible that one is more common in the population than the other (this probably is something that “we” meaning the human race knows, scientists have probably got some grasp on their relative frequency, I just haven’t found it).

But it is also possible that they do something a little different from each other. Maybe, and I am really speculating wildly here, one of them is more about lust and other other is about love. So if you have both male-attraction versions you will both tend to fall in love with men and want to fuck them. Ditto with both female versions. But if you have one of each you may be inclined to want long walks on the beach with one gender and rolls in the hay with the other. Think about THAT everyone who doubts the existence of male bisexuality.

1 I’m very familiar with dashing something off that oversimplifies one’s position because no one is likely to read it, and then being embarrassed when lots of people do. But this doesn’t seem to be the case for Ward.  When the piece became successful she added a clarification, which didn’t address the concerns I raise at all, instead tackling an entirely different criticism, in the process indicating she stood by the aspects I deal with here.

About Stephen Luntz

I am a science journalist, specialising in Australian and New Zealand research across all fields of science. My book, Forensics, Fossils and Fruitbats: A Field Guide to Australian Scientists is out now through CSIRO Publishing. I am also a professional returning officer for non-government organisations. I'm very politically active, but generally try to restrict this blog to scientific matters.
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6 Responses to You May Well Be Born Gay (Or Straight) But Not Everyone Is

  1. lindathestar says:

    Reblogged this on Lindathestar and commented:
    This is a useful and thoughtful response to the matter of sexual attraction, with science, and super nerdy addenda. Love your work, Stephen.

  2. badblood says:

    One minor complication: the early twin study, I think it was Bayley and Pillard, that found in identical twins there was concordance (both gay if one is gay) only 50% of the time. Same genes, same womb. That suggests we’re not just looking at genes, we’re probably also looking at epigenetic and environmental factors as well.

  3. Hi Daniel, thanks for the comment. My first thought was that while this didn’t entirely contradict what I was thinking, it weakened it a bit – that if genes+womb=50% then genes would be smaller so the G1G2 combination on their own probably only explain about 40% of sexual identity, possibly even less since the environmental factors would be similar for twins.

    However, on second thoughts I think this might fit what I have suggested rather well. Even aside from the fact that the small sample (when I looked it up) allowing for a big margin for error, the gay men selected to be the original pool would have included some who were G1G2 and others who were G1S2 or S1G2. Now if I am right, the G1G2s should have identical twins who overwhelmingly identify as gay. But the other two groups should have a much lower proportion, probably in the 20-30% range.

    When you combine two groups, one of who should have 80-90% of their twins being gay and the other 20-30% getting an outcome of 52% is pretty credible if there are a few more of the second group in your sample than the first.

    All this assumes, btw, that all the twins were out to themselves and the researchers – it’s possible that there were some who actually were primarily same sex attracted but were still in denial in the early 90s when the survey was done.

    When they did the same study with women, btw, they got a lower proportion of matching from twins, but not as much lower as my model would predict. However, between the fact that my model is a very crude, back of the envelope effort that barely deserves to be called a model and the margin for error on their samples I don’t think it is a contradictory either.

  4. ejaneward says:

    Thanks for such a thoughtful engagement with my blog. I appreciate your ideas here.

  5. ejaneward says:

    Here is a teaser for my forthcoming book, related to many of the questions you raise here:

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