As a scientist, I am fascinated by the new international study that found thousands of genetic variants associated with same-sex sexual behavior, and not a mythical “gay gene.”

The findings offer an intriguing glimpse into the complexity of sexual behavior. It reveals some differences in the genetics of same-sex sexual behavior between men and women, for instance. It also illustrates that human sexuality is more nuanced than many believe.

But the study is compelling to me for another reason as well. As a member of the LGBTQ community, it is affirming. The data, in essence, say that same-sex sexual behavior is a complex trait governed by a number of genetic and non-genetic factors, like height and hundreds of other traits. And just as people range from tall to short, same-sex experiences are part of the normal spectrum of human sexuality.

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Don’t get me wrong. I don’t need someone to tell me that I am “normal.” But for anyone who has gone through the difficult experience of coming out, seeing sound science validating same-sex relationships as part of the natural diversity of human sexuality is validating.

As a young scientist at Stanford, I recall reading Bruce Bagemihl’s book “Biological Exuberance.” I found solace in the fact that in the natural world there is a wide variety of pair bonding, sexual behavior, and co-parenting. From penguins to bonobos, there are countless examples of same-sex pairing. There are even instances of lifelong same-sex relationships, like among Laysan albatrosses, who stay together for life and even raise chicks together. In nature, as in science, there is no judgment. I and my wife are not an anomaly.

So this study grabs my attention as both a scientist and as a lesbian. I’ve been fortunate to work and build a career at a place that values both perspectives.

Beginning almost a decade ago, I and a group of other 23andMe researchers first started exploring studies of sexual orientation. Those early efforts were prompted in part by requests from our customers. They wanted to know more about the genetics and biology of sexuality. Like love, in general, the answer is complicated.

But my colleagues and I also wanted to conduct this research out of our own scientific curiosity.

At the time, sexual orientation was understudied. Because it’s a controversial topic, funding was limited and it was difficult to recruit participants. We felt that 23andMe, with its crowdsourced research platform that allowed anonymous participation, was uniquely equipped for this work. While there were strong opinions on either side around doing this kind of genetic study — even within the LGBTQ community, people came down on both sides of the issue — I wanted to let the data speak.

I’m proud of the preliminary work we did. But the new study — conducted by researchers in the United States, Europe, and Australia — easily dwarfs all the previous genetic studies of sexual orientation ever done. With data from nearly half a million people — including 75,000 23andMe customers who provided additional consent to participate in this research — this is the most powerful genetic study of its kind. It offers exciting lines of inquiry for future research.

The study did not find a gay gene and, frankly, human biology doesn’t work like that. Like personality and other complex human traits, sexual behavior is influenced by a mix of genetic and environmental factors. Of all the many genetic variants found in this study that influenced same-sex sexual behavior, only a handful — five to be exact — were statistically significant in their association though they had, in fact, only small effects. The thousands of genetic variants observed explain somewhere between 8% and 25% of the variation in same-sex sexual behavior.

These genetic variants are far from being able to predict same-sex sexual behavior. Intriguingly, some of the variants with the strongest associations are linked to biological pathways for sex hormones and smell, providing tantalizing clues into possible biological mechanisms influencing same-sex behavior.

But the most fundamental aspect of this study is its contribution to our understanding of the human condition. We are fascinating in our diversity and complexity, and the depth of our humanity is truly understood only when we study, appreciate, and embrace that.

Emily Drabant Conley, Ph.D., is vice president for business development at 23andMe.

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  • As a former fund-raiser, I followed your logic of full donor disclosures, until your personal disclosure, “At the GPSW we solicit donations, but not if you are a pedophile, climate denier, or a member of a murderous regime.” Never except dirty money gained unlawfully or offered from a person engaged in unlawful professional or business activities: which covers too many, if not most coastal Californians. So why not accept a donation from a ‘climate denier’? Define what is a ‘climate denier’. Yes, there are too many people on Earth adversely impacting quality of life and climate from our being alive. Assuming that by your definition ‘Deniers” justify creating and savings more people to increase the population (because it’s God’s will, or to expand the economy, or whatever), would you not accept a donation from a pro-life Christian or Entrepreneur or Investor because of their personal perspective? Explain your refusal to accept a donation from someone who’s lawful ideology and lawful conduct you disagree or don’t like. (Personal disclaimer: I support limiting family size and spacing generations but I accepted generous donations from reputable, law abiding persons with 3 or more children. Selfish maybe, but lawful.)

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