The US Supreme Court in the end of March was hearing arguments in two cases on same-sex marriage. At the same time the supporters and opponents protested in front of the Supreme Court. This caused a huge movement so news media and social media are full of news and discussions around the support or not of the same sex marriages. What a nice opportunity, then, to discuss about the effects of nature in this behaviour. The scientific findings may shed some light in this whole issue and the opinions or biases on it.
I always found quite interesting that people had the tendency to judge them as paranormal or making fun of them or at least mentioning it as something remarkable even though it wasn’t playing any particular role in their lives. The thing is that I never had a clue if there existed some kind of genetic tendencies that lead to that preference or it was all resulting from the environment. Because if they have a genetic predisposition then it should serially be discussed how much can they be blamed if someone thinks they deserve to be blamed. Also, in the case there exists a gay gene or a DNA influence on becoming gay, this is defined as not paranormal but normal. Evolution doesn’t waste traits and characteristics. Whatever trait exists, exists because it has achieved its existence through time. Without looking at the subject again I was somehow convinced that it was the environment that shapes this behaviour and I was indifferent about the issue. Until the day I decided to watch on-line the lectures of the peerless neuroscientist Robert Sapolsky from Stanford University about Human Sexual Behaviour that took place on the Spring of 2010. The whole semester of Human Behavioural Biology can be found at the Stanford University page in Youtube.
The Science and Politics on Homosexuality
So, as I was watching about the neurotransmitters and the differentiation of the secretions between sexes, Sapolsky threw the first rock on my head. There is a landmark study on 1991 with the name ‘A difference in hypothalamic structure between heterosexual and homosexual men’ by the one of the all time greatest neuroanatomists Simon LeVay. What he did was to look at the part of the brain called third Interstitial Nucleus of the Anterior Hypothalamus (INAH3). On average the size was two times bigger in males than in females. Next he measured the size of the INAH3 post-mortem on men that he knew their sexual orientation. Interestingly, the nucleus was half the size on homosexual men than on the heterosexual ones. On average gay men had a similar sized nucleus with women. This finding had a huge impact, it proved that there exists a gay brain and made LeVay very famous.
Of course this causes some questions. First of all how much was the variability of the sample. Fair amount. It wasn’t all that reliable but on the average it was about half the size. Also, where did LeVay get the brains from? He took them mostly from men that had died of HIV. Moreover, maybe the nucleus was smaller post-mortem because of its atrophy through the way of living. This is still not concluded but this study has been replicated so there is more elaboration on this.
A few years before that another group had reported another difference in the hypothalamus. A part of the brain that affected sexual orientation was reported to be bigger in women than in men. At the same time they found that the size was significantly bigger in homosexual than heterosexual men. However, the study was accepted negatively from the scientific community with both reliable and unreliable arguments. Simultaneously, the gay community viewed it as an offence from scientists to pathologise homosexuality which of course was not what the study was about. However, Sapolsky defines three possible reasons behind this. The first one is that the Dutch researchers that did the study were heterosexual men in contrast to LeVay who was openly gay so he was more acceptable by the community. The second being that due to its central-europe (Dutch) origins the study was thought as biased for proclaiming some kind of Nazi mentality. The third that LeVay’s findings were much clearer and more convincing.
Dick Swaab got threats about his life whereas LeVay was the most beloved neuroscientist of the gay community. On the first occasion with Swaab, gay men saw it as an offence, that there is some kind of problem with the brain of homosexuals when on the second with LeVay they accepted it as a scientific proof of a biological feature that should be treated as normal. Have in mind that Le Vay’s study was issued just before the Clinton elections against Buss. At that time the US government was facing a big issue on gay men in the army and Clinton was the first thing that turned to after he had been elected. So, according to Sapolsky that knew the editor of the magazine that issued the study, it was timed to be published just before the elections because they thought it would play a role.
Other Biological Differences on Sexual Orientation
There has been observed a reliable gender difference of the ratio of the second versus the fourth finger of the hands. On the average gay men tend to have the finger length ratio of straight women. Also it’s the Autoaccoustic reflex. If you plug your fingers to your ears you will hear a noise that comes from the intrinsic vibration inside your head where there is low rate sound generated. The rate differs by sex and studies showed that gay men had similar autoaccoustic reflex with straight women. The above two observations have been verified by other -although less- studies to homosexual women who appeared to have similar characteristics with straight men.
Important findings were also shown from Robin Baker in his “colossal” book “Sperm Wars“. Robin Baker was almost crucified in the end of 1980’s for his findings about the sexual competition and sexual selection that takes place inside the female vaginas and the biological adaptations of the two sexes to be more effective on these wars. Of course this is a huge topic and later little by little science has proved the reliability of his studies. Anyway, as for the homosexuals, Robin Baker proved that they showed fertility with many of them having 3-4 children. So, he stated, this is how their genes kept existing in human populations. In general gays start having sexual experiences from an earlier age than the straight ones. This provides them with better knowledge about their bodies and as a result with the chance to provide women with better pleasure. I know many women that can easily verify this.
And let’s elaborate a little more on this and discuss about transexualism in the same context. The equal-as always-society had defined transsexualism as a psychiatric disorder up to the early 1970’s. At that time in the USA a gay or lesbian was psychiatrically certified as ill. There have been a handful of significant studies on the subject. Another part of the brain that plays a reliable role in sexual dimorphism is the bed nucleus of the stria terminalis (BSTc) which is twice the size in males than in females. When the neuroanatomists looked at a very large sample of transsexuals post-mortem, they saw a very large effect on size. They had the size of the sex they had been insisting they always were, and not of the one they were born. Although you may wonder that after the operation there is a huge change in the regulation of hormones, I have to mention that the study was done to both transsexuals that had changed sex and to those who hadn’t.
Furthermore, they looked at men that had a certain kind of testicular cancer and they were treated with feminizing hormones. What was found was that the BSTc size was unaffected. This showed that the change in the body hormones doesn’t play a role in the size of the BSTc. The transsexuals were repeating that they were born in a wrong body and it seems they had a good reason for that. Behind this study was the same group of Dutch scientists with Dick Swaab on the lead.
Another founding is the differences in the so called Penile Phantom Sensation. When men have for instance testicular cancer they may have to do an operation. 60% of men that had their penises cut have experienced that Penis Phantom Sensation. This means that after the operation they reported ‘phantom penises’ and experienced ‘phantom erections’. On the contrary no transsexual operated dealt with this which is another proof that as the explanation of the word transsexual is, he is a person in a wrong body and that’s why the whole situation works in a healthier way.
The above facts raise several ethical issues on homosexuality. As I mentioned in the second paragraph, by taking into account the biological determinant in a trait automatically it is better explained and accepted by people. As a matter of fact, if there exist scientific proofs of a natural tendency then maybe people should think again when they act in a homophobic manner or when they judge it as paranormal. In the end one of the most beautiful scenes in humanity is two people being sincerely loved with each other. However, it must be cleared that there is still a lot of research to be done in order to come to more adequate findings about the effects of nature against nurture on the gay brain. Even LeVay in 1994 cautioned from being misinterpreted by mentioning: “It’s important to stress what I didn’t find. I did not prove that homosexuality is genetic, or find a genetic cause for being gay. I didn’t show that gay men are born that way, the most common mistake people make in interpreting my work. Nor did I locate a gay centre in the brain. The INAH3 is less likely to be the sole gay nucleus of the brain than a part of a chain of nuclei engaged in men and women’s sexual behaviour.” However, in later years, possibly because he had gained a reputation at that time, too, explained the above statement as follows: “This is an accurate quote, but it relates to what I showed (or didn’t show) on the basis of that one study. If one looks at the totality of research now available, including my study, the evidence points strongly to the idea that genes and non-genetic biological factors strongly influence a person’s sexual orientation, as discussed in the review article on my website.”