Is there a gay gene?

This is an outdated question. Genetics – except for a few rare diseases – ditched the concept of “a gene for something”, also known as a candidate gene. Now, whether it is cancer or height, scientists are looking for complex variations of sequences in the whole genome. They hunt not only for multiple genes but also for places outside of genes, which account for regulation.

The Study

Thanks to modern supercomputers, it is possible to compare 3.6 billion-letter-length genomes of 0.5 million people, totaling 1.8 quadrillion letters. That’s what the researchers have done in the last year, with genetics of sexual orientation in mind.

The results were presented in a publication typical for the genomic field. Authors found five places around several genes, which explained “8 to 25% of variation in same-sex sexual behavior”. They discussed functional role of those genetic variants, finding for instance intriguing connection to olfactory genes. However, the publication unusually appealed to fellow scientists:

Our findings (…) underscore the importance of resisting simplistic conclusions – because the behavioral phenotypes are complex, because our genetic insights are rudimentary, and because there is a long history of misusing genetic results for social purposes.

Communication with the public was even more careful. The team crafted website exclusively to explain the discovery (geneticsexbehavior.info) and heavily engaged with media and at Twitter.

The study obviously caused a lot of buzz. First, scientific community had heated debate about methodology (example) and ethics (example). And then, the worldwide media focused entirely on the gay gene question:

Just two weeks after the headlines downplaying the role of genetics in sexual orientation, a private company developed a test that… well, exactly checks your genome to say something about your sexual orientation. Contrary to the media coverage, contrary to the scientists – someone decided to commercialize the findings.

The Company

GenePlaza – author of the app – for mere €5.50 promises to “quantify same-sex sexual behavior”. Although they warn about lack of predictions, at the same time all charts and marketing clearly point to predictions for individuals. Misuse of the science is evident, as a user sends them genetic data, and in return receives the following assessment:

Belgian company is no stranger to this odd business.

Their shop have many more misleading apps. One of them claims to check your genetic intelligence and is advertised by “did you read more books than your genes expected to” (!). Other, for just €4, links your genome to math abilities. There are also apps for depression, neuroticism, as well as classic ancestry and health-related tests.

GenePlaza was co-founded by bioinformatician Alain Coletta and developer Robin Duqué. In recent report, Coletta said:

We try to stress the fact that this is not a disposition score, it’s not a diagnostic. We hope we’re doing a good enough job but it’s not easy to do. The Scientist

Regardless of disclaimers, the company markets their products with questions such as “how gay are you?”. The scientific evidence behind some apps is even more obscure. For instance, the intelligence app was built upon a study in which differences in intelligence were explained by genetics only in 5%.

The Reaction

Update (15th October): Authors of the original study “urged GenePlaza to take down the application immediately”.

Joseph Vitti, scientist from Broad Institute, fiercely reacted to the app. A petition to remove the app was already signed by more than a thousand people in few days – among them, some scientists heading to the annual conference of American Society of Human Genetics.

Joseph describes the GenePlaza test as both unscientific and dangerous. Why dangerous? Surprisingly, GenePlaza social media profile provides the answer:

As countries such as Uganda try to penalize gay people, the law enforcement can reach out for GenePlaza’s tool. Although that seems like a distant possibility from Belgian perspective, in reality there are still countries forcing people to exams which determine sexual history.

GenePlaza is probably aware of the controversy, as it advertised the app with a shocking ‘testimonial’ from Uganda:

Highly rural societes like where I live in Uganda, East Africa, value child labor on the farm so much that they cannot understand the relevance of non-reproductive family members or neighbors. But maybe the potential enforcement of heterosexuality against same-sex preferers, the microaggression they feel and the discrimination they suffer is crucial for their fullest intellectual and social development. Source

That text was removed from the website.

Update (24th October): GenePlaza removed the application.

The Science

Genetics of the human behavior is murky. Scientists are only beginning to gather initial insights into genetic variants, that define just small part of our characteristics. Research is mostly done on European populations.

As recent editorial in The Scientist concluded:

Given these shortcomings, why provide such tests at all? – At this point, we are purely focusing on the user having a positive, fun experience – we are not asking users to take any action. Tomohiro Takano

A positive, fun experience providing wrong data.

Publication: Ganna, A., Verweij, K. J., Nivard, M. G., Maier, R., Wedow, R., Busch, A. S., … & Lundström, S. (2019). Large-scale GWAS reveals insights into the genetic architecture of same-sex sexual behavior. Science, 365(6456), eaat7693.