Millions of people have had their DNA analysed by consumer genetic-testing companies.Credit: Getty

Joseph Vitti’s stomach turned when he opened a link an acquaintance had sent him. It took him to an app called ‘How Gay Are You?’ that purported to gauge a person’s level of attraction to others of the same sex, according to their genes.

The app’s creator, Joel Bellenson, a US entrepreneur living in Kampala, Uganda, based the test on the findings of a massive study on the genetics of same-sex sexual behaviour — even though the analysis, published in Science in August, concluded that a person’s genes cannot predict their sexuality1.

Vitti, a computational geneticist at the Broad Institute in Cambridge, Massachusetts, thinks the app was misleading — even dangerous. “There are vulnerable queer people all over the world,” says Vitti, “and this app stands to hurt them.” On 11 October, he started an online petition to remove the test. Within two weeks, more than 1,660 people had signed it.

Bellenson says the idea that his test could endanger people is an “absurd scenario” and notes that the test included a disclaimer that it could not predict same-sex attraction. But the furore over the app highlights a growing problem in the field of genetics. Researchers conduct statistically sophisticated analyses of hundreds of thousands of genomes, searching for associations between genetic variations and diseases, behaviours or other characteristics. Anyone can take the variations identified by such studies, strip them of caveats and nuance, and market a simple genetic interpretation tool online.

Scientists and genetic counsellors say that these unregulated tools can harm individuals and society, by causing anxiety, unnecessary medical expenses, stigmatization and worse. “It’s the Wild West of genetics,” says Erin Demo, a genetic counsellor at Sibley Heart Center Cardiology in Atlanta, Georgia. “This is just going to get harder and harder as we go along.”

Brewing controversy

Bellenson posted his app on GenePlaza, an online marketplace for DNA-interpretation tools, in early October. For US$5.50, a person could upload their genetic data — as supplied by consumer DNA sequencing companies such as 23andMe of Mountain View, California — and the app would place them along a gradient of same-sex attraction. The app cited the Science paper while warning users that it did not predict same-sex attraction.

The researchers behind the Science study say that Bellenson’s app misrepresents their work. The test “is not grounded in science. It is not predictive. It won’t tell you anything”, says Benjamin Neale, a geneticist at the Broad Institute and an author of the Science analysis. He and his colleagues examined the DNA of around 475,000 people and found several genetic variations loosely correlated with people who said they'd had sex with someone of the same sex at least once. But none of the variants was so prevalent that the researchers could use them to predict a person’s sexual identity.

Neale sent a letter to GenePlaza on 14 October asking that it take down the app — or remove references to his study. The next week, Bellenson renamed the app ‘122 Shades of Gray’ and added a note explaining that the authors of the Science study weren’t affiliated with the project. He says that the app has always warned users that it is not predictive, and as such does not misrepresent the study.

But the chorus of angry scientists on Twitter grew louder. Some echoed Vitti’s concern that the app could be abused. In his petition, Vitti noted that Bellenson lives in Uganda, where gay sex is punishable by life in prison. Vitti worried that regardless of the app’s scientific flaws, Ugandan authorities could get hold of a person’s results and use them as evidence of sexual preferences. Even in places where homosexuality is not a crime, LGBT+ people often face discrimination and harassment, says Vitti, who is gay.

Others agreed. “A purported test for sexual orientation, particularly one with the scientific halo of genetics, poses a very real danger to queer people living under anti-queer governments or in places where anti-queer violence is widespread,” Jeremy Yoder, an evolutionary ecologist at California State University, Northridge, said on Twitter.

Bellenson says that there are much simpler ways of discovering a person's sexual preference, such as looking at their social-media accounts. “The idea that a government would need a DNA test to figure out if someone is gay is ridiculous,” he adds.

Mixed messages

On 24 October, GenePlaza co-founder Alain Coletta removed the app from his platform. He and Bellenson both say they did not intend to hurt anyone by making the app available. And they echo other creators of third-party tools that interpret DNA sequencing data, who say that even if their tests aren’t predictive, they encourage public engagement in science2. “It may not be much better than a horoscope or a tarot-card reading, but at least it lets bioinformatics be something fun,” Bellenson says.

This argument concerns genetic counsellors, who have seen a surge in the number of people seeking help for conditions that third-party tools have identified in their DNA — often inaccurately.

Tens of millions of people worldwide have now had their genomes analysed by direct-to-consumer companies. But these firms only highlight certain genetic associations. If customers want more information, they can download their raw genetic data from these firms for further exploration.

Up to 62% of customers ultimately upload their genetic data to third-party websites for a small fee, a study published in August found3. GenePlaza, for example, offers DNA-interpretation apps that purport to assess intelligence, neuroticism and taste perception. Other websites advertise services that use DNA to explore a person’s ancestry, disease risk, ideal romantic partner, fondness for marijuana, nutritional needs, sleep habits and more.

In 2015, 23andMe learnt that its customers could feed their DNA data directly from 23andMe’s servers into a secondary application associated with white supremacists that evaluated a person’s degree of European ancestry. 23andMe shut down the app’s access to data on its servers. The company went further last year by restricting direct access to its data to select collaborators.

23andMe also warns customers who download their data that it cannot ensure the accuracy of third-party interpretation tools. Developers of these tests might base them on genome-wide analyses that find weak correlations, or associations that have been contradicted by additional analyses.

“Our philosophy has always been that customers own their data, and therefore should have the option to download it if they choose,” says 23andMe spokesperson Andy Kill. “We urge customers to take caution when considering sharing their data with third parties, especially those conducting additional interpretation of data as we cannot guarantee the accuracy or the privacy protections of those services.”

Seeking solutions

Demo says that the company and others like it should go further, by refusing to provide customers with their raw genetic data. A 2018 survey of people who had used third-party tools to analyse their DNA found that 35% felt confused by the results4. “Do we let everyone get an MRI, and then use an online tool to analyse it and see if they have cancer?” Demo says.

Vitti thinks scientists should bear more responsibility for how their results are used — especially now that geneticists are delving deeper into social and behavioural traits, such as links between a person’s DNA and their political persuasion. He argues that ethical review boards should assess whether the benefits of such studies outweigh the potential for harm. Genome-wide analyses are not scrutinized to the same degree as research on individuals because the data they rely on are pooled and anonymized. But the How Gay Are You? app illustrates how such analyses could lead to harmful outcomes, Vitti says.

Despite his distaste for the app based on his study, Neale says research must go on. “Scientists have a responsibility to describe the human condition in a more nuanced and deeper way,” he says.

But Sarah Nelson, a geneticist at the University of Washington in Seattle who has studied third-party interpretation tools, worries that her peers aren’t fully aware of how difficult their studies can be for the public to understand. And even if researchers take pains to explain how their genome-wide analyses aren’t predictive, she says, companies can still use the science as they please. Nelson predicts that third-party DNA tests will proliferate because the barrier to entry is low.

Indeed, Bellenson says he whipped together his app in a weekend. He knew enough about genetics and computer programming to write an algorithm, and find a home for it online. “Genetics and bioinformatics is so mature,” he says. “Academia can no longer control it.”