Genetics Plays a Role in The Sexual Orientation In Men ... plus ... Multivariate test successfully predicts sexual orientation 95% of the time.

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    Nov 10, 2007 12:00 AM GMT
    "Genetics Plays A Role In The Sexual Orientation In Men
    08 Nov 2007

    Is sexual orientation something people are born with -- like the colour of their skin and eyes -- or a matter of choice?

    Canadian scientists have uncovered new evidence which shows genetics has a role to play in determining whether an individual is homosexual or heterosexual.

    The research was conducted by Dr. Sandra Witelson, a neuroscientist in the Michael G. DeGroote School of Medicine at McMaster University, and colleagues at Sunnybrook Health Sciences Centre in Toronto who studied the brains of healthy, right-handed, 18- to 35-year-old homosexual and heterosexual men using structural Magnetic Resonance Imaging (MRI).

    About 10 years ago, Witelson and Dr. Cheryl McCormick, then a student of Witelson's, demonstrated there is a higher proportion of left-handers in the homosexual population than in the general population -- a result replicated in subsequent studies which is now accepted as fact.

    Handedness is a sign of how the brain is organized to represent different aspects of intelligence. Language, for example, is usually on the left -- music on the right.

    In other research, Witelson and research associate Debra Kigar, had found that left-handers have a larger region of the posterior corpus callosum -- the thick band of nerve fibres connecting the two hemispheres of the brain -- than right handers.

    This raised the hypothesis for the current study -- whether the anatomy of the brain of the sub-group of right-handed homosexual men is similar to that of left-handers.

    They found that the posterior part of the corpus callosum is larger in homosexual than heterosexual men.

    The size of the corpus callosum is largely inherited suggesting a genetic factor in sexual orientation, said Witelson "Our results do not mean that heredity is destiny but they do indicate that environment is not the only player in the field," she said.

    While this is not a litmus test for sexual orientation, Witelson said this finding could prove to be one additional valuable piece of information for physicians and individuals who are trying to determine their sexual orientation. "Sometimes people aren't sure of their sexual orientation."

    The researchers also undertook a correlational analysis which included size of the corpus callosum, and test scores scores on language, visual spatial and finger dexterity tests. "By using all these variables, we were able to predict sexual orientation in 95 per cent of the cases," she said.

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    Article adapted by Medical News Today from original press release.
    ----------------------------

    The research was just reported in the on-line edition of the Archives of Sexual Behaviour prior to the release of its printed version."

    Source: Veronica McGuire
    McMaster University
    http://www.mcmaster.ca/
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    Nov 10, 2007 12:49 AM GMT
    Ok, so does that mean if I have all the heterosexual traits, that I'm not really attracted to men? Crap! I really enjoyed the last time I took a roll in the sack for some M4M action. Is it all a lie???!!!

    I think that people who are unsure of their orientation are probably bi. So what the hell is the value of the test? I guess the military could test for those traits and just not allow men with the gay traits to be recruited. Sort of like having flat feet. That doesn't sound so positive a scientific advance.

    If you are afraid to come out, if you get tested, do you then have the 'evidence' to justify being gay and it not being your fault. So now it's ok?

    How would you use the results of such a test if it where positive, if it were negative??

  • Timbales

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    Nov 10, 2007 2:44 AM GMT
    I really don't like the idea of a genetic 'cause' for homosexuality. It basically validates the belief that we are something abnormal.

    I've been on both sides of the fence and sex really isn't all that different whether it's with a man or with a woman.

    I don't think there is any one solid reason why anyone is homo or heterosexual, and as a society we need to stop caring about the distinctions.
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    Nov 10, 2007 3:01 AM GMT
    I think the desire to posit a reason ones sexuality as either genetic or environment probably displays, well maybe to some degree, an insecurity with that sexuality. I'm homosexual, do I know why? Can't really say, but I attribute it to a combinatino fo both genetic and envinroment.

    Honestly I can't say that's right, but shifting the equation to more of one than the other doesn't change things, nor does that make me straight. Like beauty, abonormal is in the eye of the beholder. Those with a certain eye might consider it abnormal, but does it make much difference to them whether it's genetic or environment? And deos it make much difference to my daily existence whether it's genetic or environment? I'd say no, but that's just me.
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    Nov 10, 2007 3:25 AM GMT
    preference of men or women is no difference then preference to sweet tooth or bitter beer or blue jean. preference is preference. some people want to make gay issue legit just because it's genetic. but is it necessary and true?

    should the scientist find the gene that cause men and lion to like meat?
  • MSUBioNerd

    Posts: 1813

    Nov 10, 2007 3:45 AM GMT
    The fact that something is biological, of course, in no way actually makes it genetic. Nor does the fact that it runs in families.

    While some traits are indeed localized to specific regions of the brain for most people, and thus we've got an idea of the importance of Broca's area and Wernicke's region and whatnot, the brain is amazingly plastic, and sometimes patients who suffer severe trauma to an area can relocalize that brain function to another region. That's less fun than the notion that right brained people are artsy and left brained people are practical, but it's true nonetheless.

    I'd need to see a study on the heritability of the particular dimensions of the corpus callosum for a more detailed understanding, but this news report by itself is unmoving. The researchers have found a correlation between that brain structure and orientation. Correlation is not the same thing as causation. It could be, for all I know from this report, that orientation alters ones' corpus callosum, the same way that extensive musical training from an early age can alter the amount of brain tissue dedicated to the control of fingers.
  • Squarejaw

    Posts: 1035

    Nov 10, 2007 3:59 AM GMT
    I'll have to reread the article. All I got from it on a quick scan is that gays have better-developed posteriors.

    We knew that.
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    Nov 10, 2007 5:31 AM GMT
    I've always attributed the reason for my homosexuality to extreme luck! Plus that well developed posterior to which squarejaw noticed (thanks squarejaw!).
  • OutOfEden

    Posts: 100

    Nov 10, 2007 7:36 AM GMT
    Thanks for the interesting posting, I will be reading the original study and subsequent journal responses, I did have difficulty accepting a correlation in the above article:

    Medical News TodayThey found that the posterior part of the corpus callosum is larger in homosexual than heterosexual men.

    The size of the corpus callosum is largely inherited suggesting a genetic factor in sexual orientation


    To me, with rephrasing this could read: The size of the gay men's "Part A" in this study was larger than straight men's. "Part A" is a body part and therefore the size is controlled by genes, therefore sexuality is determined by genes.

    I don't think the original article wanted to insinuate causality but only the possibilty of correlation between sexuality and brain development. The development of areas of the brain, including the corpus callosum in thwe telencephalon, can be affected by our environment. Areas such as the pre, primary, and secondary motor cortex, as well as the somatosensory cortex can be effect in childhood and adulthood with the loss of a limb for example. The corpus callosum is the main connection between the cerebral hemispheres (left brain and right brain). Typically the corpus collosum in women is more developed and it has been my education that this is theorized to have occured as men focused more on singular tasks (ex. hunting) while women had to balance multiple tasks (ex. child-rearing, household, community). Again, I'm not arguing against the studying, and I really do appreciate learning about it through this thread, I just want to know more about their methods and their claims from the results!
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    Nov 10, 2007 10:57 AM GMT
    'I really don't like the idea of a genetic 'cause' for homosexuality. It basically validates the belief that we are something abnormal'

    be careful with that argument timberoo because it leads to the idea of choice. you chose to be gay so you can unchoose it. wouldn't the haters love that.

    it maybe the case for some as humanity is such a rich tapestry but i bet for the vast mojority of gay men and women, choice had nothing to do with it.

    i certainly didn't choose it. growing up in the 70s if i had had the choice i would have been straight to avoid all the hatred, family upset, abuse and general negativity. i knew from very young i was atracted to males not females. i tried the lady downstairs departments but it was not for me.

    just for the record, i love being gay, wouldn't want it any other way. if i could come back after this life, i would love to be gay again.

    also it doesn't validate abnormality at all. procreation is not a reason for humanity it is an observation.

    the genetic route to homosexuality confirms our reality! we are here and in our millions!
  • Timbales

    Posts: 13993

    Nov 10, 2007 1:15 PM GMT
    dakukbe careful with that argument timberoo because it leads to the idea of choice.


    Not in my opinion. I think human sexuality is part of our natural cognitive development. What we are attracted to, what we think feels good, what we like to look at are all complex opinions that can change over time.

    The human brain is intricate and doesn't follow any kind if logical reasoning. We form associations that make no sense at all based on our interaction with the world from the day we are born.
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    Nov 10, 2007 4:53 PM GMT
    It's obvious that we are always looking for ways of describing who we are and why we came about. Using any means available we cobble together a theory of design. In the distant past it was mythology, at some points religion said that the divine ordained us to be what we were.

    For some time now it has been various kinds of science. Phrenology said you were the way you were based on the shape of the head; it was all the rage in the 1800s (http://en.wikipedia.org/wiki/Phrenology). Freudian and Jungian psychologies had their say and so on.

    Right now genetics and environment or nurture are vogue. While they advance knowledge these are all simply ways of thinking. Ways that would make no sense other than in our day and age. Soon we will have new ways of talking and making ourselves up, new possibilities. The odd thing is that we act like these things have always been when a quick glimpse at history says no.

    I don't know if gay is a transcendent truth. While putting your cock in a guy's ass has been around since cocks and asses, what it means to be gay hasn't been the same. It was common in many societies for men to marry women, have a family, but then a male lover. Few of us would even consider that option now. I don't think its just that we are now more free to be ourselves, but that we can now talk about discovering your sexuality and using it as an identity marker, then carving out a space in society in a different way then before.

    What happens (maybe total fantasy) if people are free to love who they want. Would more people be in same sex relationships if there was no taboo whatsoever about it? Right now to be gay means to be physiologically incapable of loving a woman, but is this really true or have we created it in our head? Bi, gay, straight, have become psychological/biological/physiological truths to us, but are they really truths?

    The researchers' question assumed that gay and straight are real things that you can measure, that in some way they are biological truths. So they are going to find something. And then thinkers can take that something and make more something from it.

    This is not to say that gay isn't real. Gay is real, we deserve civil rights and equal consideration. Since the world operates like this we need to use these ways, any means ready to hand, to describe ourselves and postulate how we came about. Just maybe with an eye to that fact that it will all change someday.
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    Nov 15, 2007 12:57 AM GMT
    Genetics or learned behavior, it doesn't matter to me but, to some it does. Maybe if there is some proof of a biological nature, it will lead to our acceptance by the greater society.
    Thanks for the heads up on this.

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    Nov 15, 2007 12:16 PM GMT
    timberoo, i think we are in agreement then that we didn't have a choice even if we see different roots/routes.

    obviously we still don't really know the exact reason. to be honest i'm only really interested in the idea that 'gayness'is not a choice regardless of the reason why.

    however, i don't see why the genetic cause validates the belief that we are abnormal but the 'natural cognative development' cause, which is equally blind, doesn't?

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    Nov 15, 2007 12:56 PM GMT
    I don't think genetic is the overwhelming player in sexual orientation. REad this:

    http://yawningbread.org/arch_1998/yax-096.htm

    ( hormonal influence on the foetus!)
    Pretty sound arguments....
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    Nov 15, 2007 1:11 PM GMT
    MadApolloThe researchers' question assumed that gay and straight are real things that you can measure, that in some way they are biological truths.


    Suddenly in love.

    I find it incredibly hot to stumble across a "homo genesis" discussion where everyone remains appropriately wary of all the scientific discourse surrounding our bodies. Never really understood the astounding optimism with which people greet these studies -- as if now the Moral Majority will shrug and apologize, their bad, rather than demand a eugenic cure for their faggy babies. A quick survey of all the various biological explanations for queerness over the past couple decades almost always shows that queers are deformed or lacking in some way because, as MadApollo pointed out, you find what you're looking for.

    Happily, lesbians will be saved from this thinly veiled scientific dream of eradicating queer bodies. Seems no one over the past two decades has given any grant money to study the lesbo brain.
  • SpartanJock

    Posts: 199

    Nov 15, 2007 3:06 PM GMT
    I agree that this discussion is hot! It is refreshing to see that there can be intelligent discussion regarding 'homo genesis', including discussion from (other) scientists.

    I just want to make sure everyone is aware of the differences between the terms genetic, biological, and enviromental. Enviromental is probably fairly obvious. I don't want to give a lecture, but there are definite differences between genetical traits, and biological characteristics. Biology is influenced by genetics (i.e, gene expression), but also includes the above reference to exposure to hormones while in the mother's womb. Biology also shapes how our brains "work". Genetics strictly refers to the actual genes we have, and the transmittance of those genes via inheritance/reproduction. This is just a layman explanation, and like I said, I am not prepared to give a lecture.

    That being said, I believe there is no choice in sexual orientation, but is defined by our biology, not necessarily by genetics. If genetics do play a role, most likely there is not ONE gene that is the gay gene, but rather arises from the interaction of multiple genes that are, at this time, apparently un-related.

    Scanning the above article, I too believe that the conclusions are non-momentus, and only suggest a correlative relationship. This is similar to the fairly recent study that gays and lesbians were found to have longer ring fingers compared to their index finger.

    icon_rolleyes.gif
  • DiverScience

    Posts: 1426

    Nov 15, 2007 3:26 PM GMT
    I think the key here is to separate out the science of what they found from the talking about it.

    There is a sad fact about primary research. You have to justify it to a distrustful public and coax funding from an administration that is openly hostile. This means you have to come up with some "reason" that makes sense to the everyday joe who thinks if we have stem cells we can clone fully grown people. That's why they give the whole little "testing" spiel. It's a poor attempt at marketing. Nothing more than a, "this research is important, fund us!"

    What they found was a correlation. A correlation that suggests heritability. They make the jump to say that genetics is a likely cause because that's easier to test (the studies on environment changing brain chemistry and shape are still controversial). They've found this correlation to be predictive.

    That's the science, and about all the science there is to it. It's interesting and suggests some new places to start in understanding the functioning of human biology.



    I, however, would strongly disagree with MadApollo's assertion that this is just another new mythology. Some people may *use* it that way, but I think that the science is unlikely to change. And that the goal of understanding how our biologies work is one which is important beyond a philosophic need to fill some transcendental hole in our being.

  • Timbales

    Posts: 13993

    Nov 15, 2007 11:01 PM GMT
    dakukhowever, i don't see why the genetic cause validates the belief that we are abnormal but the 'natural cognative development' cause, which is equally blind, doesn't?


    ever see "Twilight of the Golds"?

    My major concern with a genetic 'cause' for homosexuality being found is that kind of scenario - science being able to screen for it in vitro or a 'cure' being found.
  • Posted by a hidden member.
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    Nov 15, 2007 11:03 PM GMT
    "One or my parents was a man, the other a woman, no wonder I'm f*ked up!"

    -Not me, someone else, I don't remember who.
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    Nov 23, 2007 11:30 AM GMT
    i take your point timberoo but sadly we can't alter what maybe the facts to suit what we would like.