Is homosexuality biological?

Deux femmes s'embrassent à la "Lesbian & Gay Pride" de Paris de 2005 - CC Kenji-Baptiste OIKAWA.

In a recent video, humorist Max Bird, who intends to fight preconceived ideas, said that homosexuality is caused by hormones. He thus takes up the idea according to which homosexuality is inscribed in nature, to oppose it to the idea that it is unnatural. If his intention is laudable, since he intends to fight homophobia in this way, he nonetheless falls into the trap of a preconceived idea.

Homosexuality determined by hormones: a weak hypothesis

However, Max Bird has as a mitigating circumstance that this received idea is promoted by scientists. He relies in particular on a neuroendocrinologist of the behaviour of the University of Liege: Jacques Balthazart. He published in 2010 Biology of homosexuality: one is born homosexual, one does not choose to be. According to him, homosexuality has a biological cause, and would result from the combination of a genetic factor and a hormonal factor during intrauterine gestation. His book calls for many Anglo-Saxon studies. However, what these studies show is above all that there is no conclusive evidence of a genetic or biological cause of homosexuality, but only largely extrapolated hypotheses of results that can be interpreted in different ways.

Researcher Odile Fillod, who works on communication in biomedical and psychic sciences, has published an article detailing Max Bird’s errors, weaknesses and shortcuts, as well as another article in which she highlights the methodological problems of Jacques Balthazart.

The genetic hypothesis: a lot of noise for little

The assertion of a biological determinism of homosexuality is not new. In 1993, a team of researchers led by Dr. Dean Hamer, a geneticist at the National Cancer Institute (!) in the United States, claimed to have discovered the gene for homosexuality in men. This would be located at the end of the X chromosome. To assert this, he drew blood from 40 pairs of homosexual brothers, most of whom he found five common markers on a specific part of the X chromosome. A major problem for a study that is intended to be scientific in the field of genetics: there was no control group with which to compare the prevalence of these markers!

In 1999, Dean Hamer’s study was replicated by a team of Canadian researchers under the direction of neurologist George Rice, this time including a heterosexual control group. They found no statistical difference between the homosexual group and the heterosexual group in the genetic markers present at the specific location of the chromosome identified by Hamer.

Nature, an argument against homophobia?

Yet, a number of homosexuals defend the idea of a biological cause for their sexual orientation. This would in fact relieve them of a responsibility, if not a guilt, which would otherwise weigh on them. The idea is also that their homosexuality will be better accepted socially. But first of all, it is not because it is inscribed in nature that it is not rejected by society. For example, racism considers that there are races, that these are products of nature, and its behaviour towards certain groups is stigmatisation and rejection in the name of this supposed nature.

Then, if you say, like Max Bird and Balthazart, that homosexuality is due to a hormonal abnormality at the time of pregnancy, then it could be considered a disease or a malformation that should be treated or repaired.

Finally, and a contrario, it is not because homosexuality has no essentially biological causes that it would be a choice (perverse hinted). There are many other reasons why sexual behaviour is not a choice, including unconscious psychological reasons or social conditioning (which encourages heterosexuality, for example). And then, even if homosexuality were a choice, it would not be justified to stigmatize it. The problem with the reasoning of Max Bird, Balthazart and homosexuals supporting a biological causality of homosexuality is that it presupposes that a sexual orientation could be denounced if it was not biologically determined. In short, this reasoning is based on the same principle as that of homophobes: whether to denounce homosexuality as contra-nature, or to defend it because it is the fruit of nature, nature is always called upon to judge homosexuality. What if, on the contrary, we give up the idea that we should justify our sexual orientation, whatever it is?