Many scientists wary of quest for ‘gay gene’
Neil Risch was vacationing in Hawaii when he started getting calls from journalists and his peers in genetics about a paper about to be published in the prominent journal Science. The paper, he was told, was finally going to put to rest the question of whether sexual orientation was determined by genetics.
“And I just thought, ‘OK, here we go again,’ ” said Risch, director of the Institute for Human Genetics at UCSF.
“I’ve said this multiple times: Why are we so obsessed with studying homosexuality?” Risch said. “Why not genetics of religiosity? Or genetics of homophobia? Racism? Why this?”
Risch joined many other scientists across the country in asking whether it is appropriate to
keep spending time and money pursuing a genetic explanation for sexual orientation, when other human behaviors — never mind hundreds of heritable diseases — remain underexplored.
Geneticists have been hunting for a clue in human DNA that would help explain sexuality since the early 1990s, when a scientist at the National Institutes of Health claimed to have found a “gay gene” that was passed from mothers to sons. His initial work has never been successfully replicated, but dozens of other studies have been done since then looking for other genetic ties.
The new study — the largest ever done, involving genetic material from more than half a million subjects in the United Kingdom, the United States and Sweden — doesn’t shed a lot of light on the topic, though it confirms that genetics certainly play a role in sexual orientation. The study, published Thursday, was led by scientists at the Broad Institute at the Massachusetts Institute of Technology and Harvard.
The study identified five genetic variations that were closely tied to samesex sexual orientation. But those five variations explained less than 1% of all samesex sexual behavior — meaning, many more genetic factors are at work, and it would be impossible to predict whether any given person is gay or straight based on those variants alone. Overall, the researchers found that genetics could account for up to 25% of samesex sexual orientation.
Many scientists critical of the work said that’s old news. “We already knew there was a large heritable component to sexual orientation. We knew that it was a complex thing,” said Steven Reilly, a geneticist at the Broad Institute who was not directly involved with the research. “So our understanding has not really evolved.”
The paper sparked immediate debate when it was published — indeed, it was already controversial before it was released among scientists such as Reilly who were familiar with the work. It wasn’t the results, necessarily, that anyone had a problem with, it was that the science was being done in the first place, and that it was promoted in such a well known and highly regarded journal.
No matter the intentions of the scientists leading the research, the work threatens to “pathologize” homosexuality — studying it as though it were a health problem to be solved, Risch said.
“In genetics, the world is your oyster in terms of what you might want to study to potentially help people. When all those possibilities exist, why would you study sexual orientation?” Reilly said.
It’s especially unsettling when sexual orientation is already a stigmatized, highly political issue, and it’s easy for even the most benign results to be misinterpreted, Reilly said. Already, he’d seen evidence on social media of people using the Broad Institute findings to support the longdisproved concept that sexual orientation is a choice, because it isn’t defined by one single gay gene.
“It seems like this research had a very low threshold of reward, but a very high threshold of risk,” Reilly said.
Already made aware of concerns around the research, Broad administrators made the unusual decision last week to publish, in tandem with the Science publication, several essays from scientists questioning why the study was done. Many raised ethical issues.
“Curiosity alone ... seems insufficient justification to probe the genetic basis of a human behavioral trait — and, by extension, an identity — that demarcates a vulnerable population, let alone to do so in a highimpact scientific journal,” wrote Joseph Vitti, a postdoctoral researcher at Broad.
The study authors addressed questions around their motivations both in oneonone conversations with their peers and publicly. Benjamin Neale, a Broad Institute scientist who was one of the lead researchers, said in a news conference last week that one reason he joined the project was because the data they used were already publicly available and other groups had indicated they were interested in conducting similar studies.
His team, he said, includes some of the most skilled geneticists in the world, and he believed their work would be more socially responsible and scientifically rigorous than that of any other.
He added that there is value in satisfying scientific curiosity. “Doing science to learn about ourselves is really a feature of what I think motivates a lot of us to be a scientist,” he said.
Marc Breedlove, a neuroscientist at Michigan State University, said that same motivation was what compelled him to conduct studies of the ties between biology and sexual orientation when he was a professor at UC Berkeley in the 1990s. Specifically, his research found a correlation between finger length and sexual orientation among women.
“I’m a total believer in pure knowledge,” Breedlove said about the controversy surrounding the new Science paper. “I would be absolutely in favor of finding out which genes influence sexual behavior, just to know more about ourselves. Most people really do identify as being straight or gay, so this gets at the heart of identity: Who am I? That’s always going to be of interest to us, and that seems perfectly natural to me.”
Risch said that though he understands that reasoning, he questions whether people’s desire to understand sexuality is really just about curiosity. For so long, the question of determining a “cause” of samesex sexual behavior was framed negatively.
“It was like, who’s to blame? Whose fault is it?” Risch said. Finding genetic answers to sexual orientation may offer some people comfort — but it’s troubling that they should need that reassurance at all, he said.
“This is what probably bothers me the most,” Risch said. “People should not need this. Nobody should need this to feel good about themselves.”