The Science Behind Sexual Orientation

Disclaimer: I am about to discuss a very touchy subject which many people have extremely strong beliefs about, myself included. I am going to keep all of my information strictly scientific and fact-based, and I would appreciate it if everyone would do the same. For science’s sake, let’s treat this like any of the other topics on this website.

Let me start off by saying that this is in no way an attack on people’s sexual preference, nor is it male-female-symbols-gender-signs-vector-two-colors-48979320my way of putting people into a group and stripping them of their individuality because of how they identify. I have family members and friends who are both gay and straight, and whom I love equally. This is simply my way of getting a better understanding of why we are born attracted to the same sex, opposite sex, both, or neither. Is it nature, nurture, a little bit of both? Could there be such a thing as a ‘gay gene?’ Well, hopefully this post will shed some light on those questions for my sake and yours.

First we should talk about sexual orientation as a whole, before getting into details. According to the American Psychological Association, sexual orientation is a complex thing that many researchers believe depends on a variety of components such as genetics, hormones, development, social factors, and cultural influence. In other words, there really isn’t a general consensus as to why we identify a certain way. This idea about sexual orientation being inconclusive actually makes a lot of sense in the broader spectrum of things. When you grow up inherently liking (or not) what you like, it can be difficult to pinpoint an exact explanation as to the when, why, and how your attraction occurred. Besides, many people believe that the reason humans are straight is to reproduce, a perfectly logical way of viewing things, but if we–for argument’s sake–say that is the case, then why are people gay?

Although, just like all sexual orientations, the true reason why people are homosexual is inconclusive, there is a lot more research done in an attempt to explain being gay than any other orientation. This chain of studies started with Simon LeVay’s observational study on the human brain. He took the brains of male, female, and homosexual cadavers and reported that the “hypothalamus was smaller in homosexual men than in heterosexual men” and smaller yet in women. However, Levay’s sample size was small, his study observational, and his record keeping poor. There was also a confounding variable that had a potentially extreme effect: all of the cadavers died from the HIV/AIDS virus, which has an enormous effect on the brain. Although this type of study was never repeated, it sparked theories from several other researchers, and it continues to today.

Gay Gene? A later study by Dr. Dean Hamer is where the genetics and homosexuality 3755284016_crop380w_iStock_000021997198XSmall_xlargerelationship came into play. Hamer took a non-random group of homosexual men and examined their family history. In total, there were “76 gay men and 40 gay brother pairs.” Through DNA linkage analysis, he and his team examined the men and found a common set of DNA markers (called Xq28) on the end of an X Chromosome, and it was found on 33 out of the 40 pairs of homosexual brothers. This caused Hamer to conclude not that there was a ‘gay gene’ per say, but that “statistical evidence of such genes exist.” Another larger study conducted later on by the NorthShore Research Institute backed up Hamer’s conclusion when they collected “blood and saliva” from 409 pairs of gay brothers. They wound up finding the same Xq28 marker as well as another 8q12 marker, but they did not conclude that this proved homosexuality was a result of genetics, just that there was a possible positive correlation.

Proving the inherited idea wrong: Since Hamer’s study, there has been a lot of backlash and many people have set out to prove this idea false. One fault that was found in his study was that he didn’t test the heterosexual family members to see if they carried Xq28 nor did he explain why it wasn’t found in the rest of the brother pairs (Source). After finding this flaw, Rice and Ebers, repeated Hamer’s experiment, but they found that “the gay brothers were no more likely to share Xq28 marker than would be expected by chance.” Other studies that go against this idea of genetics are the separate twins studies by Bailey and Pillard and Dr. Neil Whitehead. Both researchers hypothesized that, if being homosexual was strictly genetic, then more twins would bear the same sexual orientation than biological brothers and sisters. However, this was not the case for either study. Whitehead summed up both of their conclusions when he said “At best genetics is a minor factor.”

So with all of that said, what should we believe? Well, the choice is up to you, but there truly isn’t a way to determine what’s correct and what isn’t. The idea of a gene certainly is plausible, but an entirely separate study by Brandeis and Temple Universities suggest that many people are more willing to believe in the ‘gay gene’ because of how sexual-discrimination1much emphasis the media puts on it.
We can conclude that this theory is also likely because it is similar to the relationship between media and vaccines.There is also little information on gay women and bisexual people to compare research to. Some people may not need to know what causes their sexual orientation and might think that the entire question is completely unethical to begin with. Others will tell you that sexual orientation is a choice, no matter what research you try to show them. With that said, the best conclusion for now is probably the one by the American Psychological Association which states “Sexual orientation is a complex thing.” That’s something I think everyone can agree with.

3 thoughts on “The Science Behind Sexual Orientation

  1. Jenna Campbell Post author

    Anthony – Thank you very much for the compliment. I definitely would have to agree about the media, I think that if I ever expand on this in a different blog, then I would definitely look more into that. The media has an enormous hand in what people thing about scientific topics like we’ve been learning about in class–pertaining to vaccinations. What do you think about the media in science? Do you think they should be able to make claims that aren’t backed up by research (kind of like our blogs)? I’m just kind of curious because I’m a journalism major. Also, in regards to my blog, would you say that the media does have a hand in deciding whether or not there is a gay gene, as the study I mentioned toward the end suggests?

    Rory – In response to your questions, I can’t say I’m exactly sure. I definitely don’t think that there is some sort of advantage so to speak. Is there a reason you thought of that? According, to everything I read, there isn’t much information on biological characteristics. In fact, I didn’t even include it because there was nothing pertinent to homosexuality. However, I’m sure there is probably a function. There was no named mechanism, of course, considering results were inconclusive. There is this theory I would be curious to hear your opinion on. Sigmund Freud believed we were all born with something called Innate Bisexuality or, in other words, we are all born bisexual and our environment will later influence us to specify a certain identity. What would you say to this idea?

  2. Anthony Joseph Martin

    First of all I think you did a very good job explaining yourself in the disclaimer. Personally peoples opinions on this sort of topic do not bother me, why they insult other people I don’t know but I think it is sad that it is necessary. Before you stated that Hamer did not check for the Xq28 in the heterosexual brothers, that question immediately popped into my head. I feel as if that is a huge flaw in this, and he may have been able to support his hypothesis better. I also think its disturbing how much influence the media has over this topic specifically. People get fed all types of opinions and anecdotes and it seems to do a whole lot more bad than it does good.

  3. Rory McGowan

    It’s a shame that this topic even needs a disclaimer when being discussed. Clearly, there is some sort of advantage to some individuals being homosexual–it occurs throughout nature, as well. Take this particular set of animals, for example Do you think that there is some sort of genetic advantage to being homosexual? Do you find there to by any sort of function that homosexuality fits in order to maintain a healthy population? This issue is in now way new–it has merely been exacerbated to the point of preponderance by the proliferation of communication-based technology. Regardless, I believe that there is a lot of research to be done in regards to the objective science as to WHY people are gay. Good article.

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