Gay Genes?
October 29th, 2007 by Dr. Barry Starr
Gay Pride Parade in BrazilA big federal study is underway to identify the specific DNA changes that contribute to being a homosexual. Note that scientists are not investigating whether or not being gay is genetic. The evidence is already pretty strong at this point that there is a genetic component to being gay. What they are looking for are the specific changes.
For example, one study showed that if one identical twin was gay, then the other was 50% of the time. If the two brothers were fraternal twins, then the odds dropped down to 22%. And if one brother was adopted, the odds were only 11%.
Another more comprehensive study gave similar results with both twins in an identical twin pair being gay around 32% of the time as compared to 13% of the time for fraternal twins. Lots of other studies have been done that show the same trend even if they don’t have the exact same numbers.
These results strongly suggest genes are involved because identical twins share the exact same DNA. If both twins in an identical twin pair have some trait in common more often than do fraternal twins, then odds are that genetics plays a role.
These twin studies show that being gay is at least partly genetic. So the new study is really just looking to explain explain the older results.
That said, I am torn about whether I want this study to succeed or not. If it is successful, that’ll shut up all those people who maintain that sexual preference is purely the result of personal choice. In my opinion, quieting those folks is a good thing. But finding the gay gene(s) may have unintended consequences. Some people may see being gay as akin to a genetic disease like cystic fibrosis or sickle cell anemia. As something to be minimized through carrier screening, embryo selection, or even abortion.
Scary, but I have heard people say things like this. Just the other day someone asked a friend of mine if homosexuality was genetic. They weren’t merely being curious. They were hopeful that there was a gay gene so that homosexuality could be eliminated from the human population at some point. Yikes!
And that was here in the San Francisco Bay Area. Who knows what they are saying in Wyoming or Texas. Do we want to find the gene(s) responsible for homosexuality? Or are some things better left unknown? Comment below.
Dr. Barry Starr is a Geneticist-in-Residence at The Tech Museum of Innovation in San Jose, CA.
latitude 37.3316, longitude -121.89
Tags: gay, genes, genetics, homosexual, KQED, kqedquest, QUEST, Science
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the posibilities are in fact very scary
say they develop a pill to switch off you gay gene; or to turn it on; gay people could want to use it as well
Your comment got me to thinking about X-men III and the shot they developed to shut off the gene that gave mutants their special powers. Some folks wanted to take it to fit in and others wanted to remain true to who they were.
[…] Last blog I talked about some studies that link homosexuality and genes. The most powerful studies are those that compare identical twins to fraternal twins. These studies show that both twins in an identical pair are more likely to be gay than are both twins in a fraternal pair. Since identical twins have the same DNA, this suggests that something genetic is going on. […]
The research seems to assume that there is a genetic component to being gay. I’m not entirely familiar with all the work done on the subject, but isn’t it a bit biased to base this assumption on the occurence of homosexuality in identical/fraternal brothers? Knowing a few pairs of twins, they seem to do just what the other does, whether consciously or not. This introduces an environmental facet- how have the twins been influenced?
If genetics are to come into the question, what work has been done on the children of men who were gay and then later had children in a heterosexual relationship, or conversely, had children and then adopted a gay lifestyle? I think perhaps this may be more indicative of genetics- but again, there is always the chance that a child could have been influenced by his/her gay parent.
I’m not exactly sure what to think on the matter at this stage- it does confuse me a little. I know for a fact that there ARE people who choose to be gay- and this is the most common scenario. I do however, know gays who seem to have just been born that way, and knew it from childhood.
At any rate, it’s an interesting question- genetic or not- though i do think that the statement “Since identical twins have the same DNA, this suggests that something genetic is going on..” may be a little premature since there are so many other reasons that people could be gay…be it environmental or psychological, biochemical… it doesn’t have to be an in built tendency.
The key is to compare fraternal twin pairs to identical twin pairs. Both kinds of twin pairs have similar environments but the identical twins have the same DNA. So if something happens more often to two twins in an identical pair compared to the two twins in a fraternal twin pair, then genes are probably involved.
The elephant in the room here is whether identical and fraternal twins really have the same environment. Do two twin boys who look alike really have the same environment as two twin boys who look different?
This is where separated twins can help. There are some identical twins who are separated and raised by different families. If these twins are gay more often than fraternal twins from a similar situation, then genes are almost certainly involved.
Unfortunately, since homosexuality is relatively rare and separated twins is even less common, there hasn’t been a lot done on this. One study did show that identical twins in this situation were both more likely to be gay but the study was very small.
I wish there was a gay gene then may be we culd make a go gay pill. I wish I had some at school as there was this guy he was so sweet I just fell for him I never new I culd feal that way. I never did know why I liked him at 1st. Just kiding about makeing a go gay pill realy I am.
Do we realy need to find the gene if we do will we have a gay test. Will that be used on teachers as a lot out there think it is gays that harm children. Why not spend the time and money in finding the gene that makes men abuse and rap kids and not be picking on thows that are openaly gay as it is not gays that do harm to peopel. I know am geting off the beat just a bit but I say this as growing up gay and geting beaten up and haveing peopel say don’t you be going near kids. I was just a kid my self so I say it a gane lest spend the time and money in finding the gene that make man an women yes women harm children. Or fine the gene that make pig headed peopel.