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1. So it is my mother's fault after all. Hmmmm I can't wait to discuss this with my shrink next week. Good to know.

   Posted by: Donald | Feb 21, 2006 4:02:44 PM

   
   

2. "What's really remarkable and very novel about this is that you see something in the bodies of women that is linked to a behavioral trait in their sons," he said. "That's new, that's unheard of."

   OK, why do these experts sound so breathless? I don't have an advanced understanding of genetics or natural selection, but I figured this out a long time ago from employing a little bit of common sense. When you look at a particular trait, like homosexuality, always ask yourself whose reproductive fitness is increased the most by the existence of that trait. In the case of a mother with a gay son, for example, the son's genetic material isn't more likely to survive to the next generation, the mother's is. She probably will have more offspring after she gives birth to the gay son; and he's likely to stick around to help nurture and protect them, unlike his straight brothers, who'll run off to chase females (available cock was in fairly short supply hundreds of thousands of years ago when small groups of protohumans were the norm)and will be more concerned with protecting the resulting offspring. This fits nicely with the findings that second sons are much more likely to be gay.

   Posted by: Tom | Feb 21, 2006 4:13:06 PM

   
   

3. Interesting Tom. I am second child of three, oldest son and my younger brother is also gay.

   Posted by: Donald | Feb 21, 2006 4:24:25 PM

   
   

4. I always knew my mother made me gay, I just thought it was because she took me to the opera and to Barbra Streisand movies.

   Posted by: Sam | Feb 21, 2006 4:42:51 PM

   
   

5. 4 kids (3 boys, 1 girl) all 3 sons are gay.

   But if you met Mom...you'd know that a Teamster wasn't gonna come out of her.

   Posted by: Myackie | Feb 21, 2006 5:15:27 PM

   
   

6. Hmmm....be careful for what you ask for. Genetic defects can be fixed or worse, tested for and eliminated.

   Posted by: Mitch | Feb 21, 2006 5:29:54 PM

   
   

7. There is only one little prob here. "The Journey of Man" was just on PBS last night and, the geneticist/biologist Wells says that he used the X chromosome to trace the migration of man out of Africa. Wells says (and illustrates in the special) that he used the X Chromosome because it is UNCHANGED by heredity (meaning that a male gets his X chromosome directly from his father with NO contribution from the mother). Obviously, someone here has the wrong info.

   There is another part of our DNA (mitacondrial, I think) that we get directly from our mothers unchanged. And, this part of our DNA has been used to trace every human on the planet back to a couple (possibly ONE) woman in Africa. So, since we are all from essentially one Black African Women, we must all be gay.

   Posted by: Peter Everhard | Feb 21, 2006 7:48:06 PM

   
   

8. Peter, in our nuclear DNA we get our X chromosome from our mother and Y from our father. Our mitochondrial DNA comes from our mother in whole, unchanged. Due to DNA sequencing mutations occuring at predictable intervals there is variation in mitochondrial DNA, so not everyone's is the same. But the variations can be used to trace back as you say.

   For example, suppose you have four groups of people with sequences of DNA that are identical except for these common subsections:

   Sample 1: GGTACC
   Sample 2: GCTACC
   Sample 3: GGTATC
   Sample 4: GCTACG

   From this, we can conclude group 1 is either the direct "parent" or "child" group of group 2 and group 3 given just one mutation difference between each, but not group 4. Group 4, based on the existence of group 1, is likely the "child" group of group 2 since it is one mutation different than group 2 and two mutations from group 1. In relation to group 4, group 3 is either a much older great-grandparent group or a "aunt" group with groups 2 and 3 being sibling groups. Now just imagine multiplying the complexity of this over more than just 6 sequence pairs. :-)

   Posted by: Craig | Feb 21, 2006 8:21:56 PM

   
   

9. You are correct, of course. I should have typed Y instead of X. The chromosome that makes you MALE (the Y) comes from your father UNCHANGED. See info on The Journey of Man @ http://news.nationalgeographic.com/news/2002/12/1212_021213_journeyofman.html

   There have been multiple studies tracing all humans alive to a very very small number of women in Africa (possibly one woman as I said). So, it makes very little sense to even imply that sexual identity is controlled by something passed from mother to son.

   Posted by: Peter Everhard | Feb 21, 2006 8:56:23 PM

   
   

10. My brother and I are both Gay, but I'm the good looking one.

    I know two sets of twins, one boys, one girls, and in both sets, only one twin is Gay.

    It's interesting to have some proof of what we've always known, but I worry about the dangers of having a genetic test for homosexuality. Will parents choose to abort a Gay child? Will employers require a blood test that could exclude Gay job applicants? Could it be presented as evidence in a court of law?

    I guess every rose has it's thorns.

    Posted by: Jay Croce | Feb 21, 2006 9:55:55 PM

    
    

11. I am extremely worried that in a future world where eugenics or designer babies are the norm, homosexuality may be eliminated in favor of 'desirable' traits.

    Posted by: Dan | Feb 21, 2006 11:23:00 PM

    
    

12.    So, it makes very little sense to even imply that sexual
       identity is controlled by something passed from
       mother to son.

    Not really. Over thousands of generations there is genetic divergence so long as in-breeding is not rampant. That's why we have a diversity in hair color, eye color, amount of body hair, prevalence of baldness, etc. While some of these are equally contributed to be each parent, some are not or first require the mother to be a carrier to be activated.

    There also may be other factors involved, like birth order of the child and the mother. Other studies have shown that the children of women who have multiple older brothers are more likely to be gay. And children that have multiple older brothers are more likely to be gay. I believe those studies as I can see both in my own family. My mother was the 8th of 10 children and has 6 older brothers. Two of my mother's three children are gay. My mother's youngest brother, the 10th child, is also gay. I do believe homosexuality is one way that nature tries to keep population in check and keep the proper balance between the male and female population. Tom's comment above is also very cojent to this theory as well.

    Posted by: Craig | Feb 22, 2006 1:41:45 PM

    
    

13. Like I said, I don't know the ins and outs of genetics, but with that said, I don't think homosexuality is the genetic trait, I think the genetic trait is the propensity to produce homosexual offspring. Thus at conception every child would have in its genotype the potential for being either gay or straight. What would be different is the phenotype, which arises from the interaction of the individual’s genes and the developmental environment in the uterus. Some women create within themselves an environment more predisposed toward creating a homosexual phenotype. AND, I'm guessing that there is no way to test for traits at the level of phenotype--so the fear of mass abortions of gay fetuses is unfounded. That'd be like trying to determine whether a fetus has a particular sworl in its right index-finger fingerprint (fingerprints are also phenotype traits). Our genotype is full of the potential for variation. It may be that every person has in hir genotype the potential to be gay. So, what are they gonna do? Abort everyone?

    Posted by: Tom | Feb 22, 2006 2:00:13 PM

    
    

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