Gay genetics

Thanks to Michael I have been educated on what scientists are up to while trying to prove a "gay gene" exists.

From the New Scientist comes the article titled "Gay Genetics". (see here)

This is an interesting article. However I ask that you take what read with a dose of salt. Seems to me the scientists are long on book learning and short on common sense. They are jumping to conclusions, conclusions that are not supported by the evidence they have generated.

They state "...mothers and aunts had more children if related to a gay rather than a straight man. Mothers of gay men averaged 2.7 babies, compared with 2.3 born to mothers of straight men." This is an interesting statistic, however later in the article comes "The team suggests that gene variations on the X chromosome make women more likely to have more children, and men more likely to be gay. "We think of a gene for male homosexuality, but it might really be a gene for sexual attraction to men," says Simon LeVay, a neuroscientist at Stanford University and a writer on sexuality." See what I mean about jumping to conclusions? The fact that women who have gay children also, on average, have more children they think helps to prove the gay gene exists. That the gene, when it appears in women, makes them women more sexually attracted to men. That these women have sex with men more often which is why they have more children.

How about applying some common sense to this conclusion? What conclusion can an average man reach from the statistics they generate? I'll tell you what conclusion I reached. Most of the women we are discussing were using birth control of one kind or another. That conclusion is the only one that can be reached with any degree of certainty. My wife and I had 3 children. The fact that we did not have more then 3 is because we practiced birth control. My parents did not believe in birth control and they had 11 children. The reason my Mother had more kids then my wife did is not because my parents engaged in sex more often then my wife and I did. Knowing my parents, knowing that they did not use birth control and knowing that they only had 11 kids, I would venture to say they engaged is sex less often then my wife and I did, but I can not say this for certain.

The only thing the statistics prove is that, on average, all the subjects were using birth control and then perhaps the further conclusion that, for some reason mothers, who happened to have gay children either wanted more children, on average, or just used birth control less effectively. Without including this consideration in their reasoning the scientists are missing the boat.

Perhaps these statistics could lead to some interesting paths that would need to be explored. For example, what types of birth control did the mothers use? Is it possible that they became pregnant while using birth control? Some methods of birth control are more effective then others, none are 100% effective. Some methods of birth control involve monkeying with hormone levels in the woman's body. Do some forms of birth control make you more apt to have gay children when the "ooops" occurs then others? Is it possible it is not a "gay gene" we are searching for but for how the baby develops within the womb after the pair of chromosomes are united? Is it not also possible that these statistics could even prove that no gay gene even exists? This would be a stretch, but perhaps through some "maternal instinct" the mothers sensed there was something "wrong" with their child and were more apt to want more children so as to replace the defective child?

As for maternal instinct I believe this might be possible. When my wife was breeding dogs, one of her dogs had a litter of about 9 pups. The mother refused to allow one of the pups to nurse. She would keep nuzzling it away from her. My wife could not figure out why she abandoned the pup and tried to nurse it on her own with a bottle. By the end of the day the pup was dead. From this I think I can draw the conclusion that either my wife is a terrible nurse or the mother instinctively knew the pup had something wrong with it and did not want to waste any of her precious milk on the hopeless case.

Anyway, all the article proves to me is that the scientists are falling into one of the traps that they really should avoid. They have already reached a conclusion and now they are setting out to prove that the conclusion is correct. They almost blindly examine results. Perhaps not completely blindly, but with blinders on. The article proves it.


Blogger Michael said...

I think you are trying to read a little bit too much into that study.

That study doesn't prove the existence of a "gay gene". It simply showed that women rated to gay men (mothers and aunts) on average had more children.

Since these women would mostly have had other children before the sexual orientation of the child became obvious, it would be rather unlikely that they had more children because of a "behavioural response" to the gay child.

There may be many reasons why these women had more children.

What conclusion can an average man reach from the statistics they generate? I'll tell you what conclusion I reached. Most of the women we are discussing were using birth control of one kind or another. That conclusion is the only one that can be reached with any degree of certainty.

Okay... I can tell you that what you wrote up there is entirely conjectural.

As before, this study doesn't prove one thing or another and the study authors doesn't say it proves the existence of a gay gene either. However, Ockham's razor tells us from this observational study that there may be an inheritable aetiology to this observation (and thus it would be worthwhile to search for genetic components that could explain such a result - that may or may not exist).

Homosexuality is obviously not entirely genetic. There have been identical twins where one is gay and the other is not. It not being entirely genetic does not mean that there is not a genetic predisposition and it certainly doesn't not mean that it is not biologically driven.

Where one twin is homosexual, the other is much more likely to be so (compared to two random people or two siblings).

As I mentioned before, sexual orientation is most likely set during the development of the brain. BTW, the author of that study, Simon LeVay is quite a prominent research in this field. He was the one who initially described differences in the size of part of the hypothalamus between straight and gay men. That original research has since been criticised in terms of its methodology but it is nevertheless still a very interesting finding.

Michael Tam

12/10/2005 11:29:00 AM  
Blogger Little David said...

I am not saying homosexuality is not genetically driven.

I am not agreeing to the other side just yet either.

I am saying the article, as it is written, seems to prove the researchers have already decided that it is. The conclusions pointed out to shouts that they have already made up their minds.

I am impressed by your willingness to not be a bigot. You are willing to admit, and even point out, the evidence that points contrary to your position (such as the evidence of twins). You will acknowledge the weakness of your own argument. You are still exploring.

You, Michael, are not a bigot. You might be wrong, but then again I too might be wrong. You are at least willing to explore your position as am I.

I think I am starting to love you Michael! But I am going to continue to only have sex with my wife. Grin.

12/10/2005 12:12:00 PM  
Blogger Little David said...

And just in case anyone feels uncomforatable by my profession of love for Michael, think of it in these terms. In terms you already know... best friends. We just do not jump in bed together.

12/10/2005 01:08:00 PM  
Blogger Michael said...

I'll sidestep your declaration of love just for now... ;-)

The conclusions pointed out to shouts that they have already made up their minds.

I'm sure Simon LeVay has. He is a prime proponent of a neurodevelopmental aetiology of sexual orientation and he is probably right though the exact mechanism is far from elucidated.

LeVay's initial presentation at a conference on his work on the differences in the hypothalamus (on MRI) between straight and gay men is legendary. At one point, he was asked by a sceptic in the audience how exactly he knew that the person whose MRI image of the brain was actually gay; to which he responded, "because that is my brain"...

Michael Tam

12/10/2005 09:22:00 PM  

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