The idea of a gay gene, and why we are searching for it extends from, I think, a very basic misconception we have about genetics and human choice. Society seems to have come to a point where things are either purely a product of biology via genetics or our own free will. This is wrong on several levels.
First, it's not just genes vs. choice. We also have found that much of what we'd consider biological has to do with epigenetics and womb environment. Further, RNA plays a very complicating role, that we barely understand. Take for example cloned cats: they can look nothing alike whatsoever, a clone of a tabby can turn out to be a calico. Genetics don't even determine the sex of some reptiles. We've recently found that men can pass down stress levels through RNA. Even if something is purely biological, it's not necessarily genetic or DNA based.
Secondly, and perhaps more importantly, those defending gay rights have unnecessarily placed their moral authority on shaky ground. What if we found out that expectant mothers could take certain dietary supplements and virtually guarantee their child would not be gay? What of the studies that say birth order is highly predictive of homosexuality? Would that open homosexuality back up as potentially a moral failing (albeit the mother's)? What if a study comes out that says a child's position in his peer group determines sexuality? Should any of those questions matter when deciding on basic human rights of an individual?
The problem is that the morality of homosexuality should never have been a question of genetics in the first place. What if homosexuality was a choice people made? So what? That wouldn't make it morally wrong. How did we get to the point where we are basing morality on what is essentially trivia, i.e. the root cause for sexual preferences? Homosexuality wouldn't be immoral even if it was a choice. Stop giving up that ground, because it will keep the debate on the morality of homosexuality open for decades, if not centuries, as we untangle the vast mysteries of how DNA, RNA, epigenetics and environment (and perhaps things we aren't even currently aware of) interplay. If we base our view of the morality of homosexuality on biology and genetics as we unwrap this confounding enigma the very nature of each gay person's identity will swing back and forth with each study. Gay people deserve a more certain future than that.
Can't we just say that being gay is either moral or it's immoral, regardless of the cause? If you biblically support the notion that being gay is immoral, is your faith subject to findings of science? If you believe that being gay is perfectly moral, would it matter why the person was gay? If you think gayness is moral, shouldn't it be moral simply because it's personal, regardless of whether or not it's a personal choice or a personal characteristic from birth or any other personal reason?
Basing morality on genetics is also problematic for its implications on other aspects of humanity, and especially sexuality. One that has come to the fore recently has been pedophilia. Recent findings have given support to the notion that pedophilia may be at least partially, if not largely, biological. Which, while unconfirmed, would make some sense. If one aspect of sexuality is biological, why wouldn't other ways in which it varies from the majority also be biological?
The problem on the horizon here is that since we have based much of the argument on homosexuality not being immoral on its likely biological "from birth" grounds, we then will inevitably have to apply that same logic to pedophilia if we find that pedophilia is largely biological. If being gay is okay because it's not a choice, being a child molester must also be okay if it's not a choice.
That last sentence will upset people, and it should, because it's wrong, but not for the reason most people think. It's not wrong because of some false equivocation between the two scenarios, like many who would get angry about it will claim. The equivalence in application is sound. The wrongness comes from the fact that moral justification shouldn't be based on genetics.
A while back, certain evolutionary biologists received a lot of flack for studies that argued that rape may be at least partially biological. Those studies were largely abandoned, not because peer review discredited them as frauds, but because nobody really wanted to defend them or even attempt to replicate the results, and anybody who did was immediately cast as a fringe scientist. That was really a pre-cursor to what we are now seeing with pedophilia. Since we had built our notion of the morality of rape upon a scaffold of "genetic pre-disposition would make it moral" then we had to just do away with the studies as quickly as we could, because rape is very obviously immoral. Do we know if a propensity to rape is biological? No, the studies never came close to having valid proof of that, but we don't know that mostly because it's career suicide to even study it at this point. The reasons why men rape have largely gone unstudied, because almost nobody wants to study it, and those who do want to study it can't get funding for it and risk their tenure if they forge out on their own. Studying the causes of rape gets you branded as a "men's rights" apologist almost immediately. The thing we all missed though is that it doesn't matter when it comes to moral justification. Rape is immoral because we have decided that sexual violation of another without their consent is morally wrong. It doesn't matter if the person has a propensity to be nearly compelled to do it from a moral standpoint (though it may matter from a treatment and prevention standpoint, more on this later).
The problem is especially coming to a head with studies on child molestation prevention because it seems as if we have two choices: 1) Load the dice against any genetic explanation, and then possibly come up with poor solutions for prevention because we don't understand the problem or 2) acknowledge that pedophilia is partly biological and thus can't be immoral. Neither of these solutions are ideal, yet if we stick with the genetics as a moral justification line of thinking, it's really all we have. Already, we are seeing a backlash to these studies of a possible genetic/biological basis for pedophilia. People don't like that it's being studied because of the possible moral implications. This is exactly backwards.
We must acknowledge that genetics are important to understand when it comes to prevention and treatment. We can all agree that having less child molestation is a good thing, and I think it's fairly uncontroversial to say that understanding the cause of something is a major key to understanding how to prevent it. We must also acknowledge that a possible genetic cause of a sexual preference is irrelevant to its morality. Morality of sexual choices come down to the harm it levies on other human beings. Rape is wrong because of the physical and emotional harm it does to the victims, not because it was a choice somebody made. Child molestation is wrong because we agree that children can not consent to sex and the vast evidence of the physical and emotional toll it takes on its victims. Homosexuality is not wrong because there is no compelling evidence it does any harm to anybody.
Finding a gay gene isn't important from any standpoint other than pure scientific inquiry. We have no real reason to try to "treat" and prevent acts of homosexuality. We shouldn't really care why people are gay, other than pure intellectual curiosity. Yet, we search for it desperately out of a misguided search for a bad way of giving it moral justification. Rape and pedophilia, on the other hand behoove us to understand everything we can about any possible biological factors, so that we can best understand how to limit their devastating impact. Yet we discourage study of those out of fear that we may just find that they are very biological and determined from birth. This is completely backwards. Maybe rape and pedophilia are purely choices people may make with no genetic basis whatsoever, but we certainly need to study every possible avenue, and not paint those who do as morally bankrupt people themselves.
As a victim of child molestation, part of me wants to be able to paint the person who did that to me as an evil human, who chose evil, and is worthy of all the hatred that could ever be possibly hurled at him. But the part of me that wants this to never happen to anybody else just wants to understand everything that might be done to prevent it. If it's genetic and he "couldn't help it" well, whatever, it was still morally wrong; I just hope we can come up with a solution for the next child. If it turns out it was purely a choice, well, then we can go confidently down avenues of preventing people from making that choice. If it's (as I think likely) somewhere between those two extremes, again, we are hopefully going down the path of prevention as informed as possible.
I'll be curious about the studies on the genetic factors of homosexuality because I'm intellectually fascinated by genetics and neuroscience, but it won't have any impact on the respect I have for gay individuals and their sexual preferences. I'll be personally interested about studies of the genetic factors in rape and pedophilia because they may hold keys to making our world a better place.