Why somebody is gay

In the U. Despite these numbers, many people still consider homosexual behavior to be an anomalous choice. However, biologists have documented homosexual behavior in more than species , arguing that same-sex behavior is not an unnatural choice, and may in fact play a vital role within populations.

In a issue of Science magazine , geneticist Andrea Ganna at the Broad Institute of MIT and Harvard, and colleagues, described the largest survey to date for genes associated with same-sex behavior. By analyzing the DNA of nearly half a million people from the U. Numerous studies have established that sex is not just male or female. Nonetheless, misconceptions persist that same-sex attraction is a choice that warrants condemnation or conversion , and leads to discrimination and persecution.

I am a molecular biologist and am interested in this new study as it further illuminates the genetic contribution to human behavior. This study pulled the information for , people across the UK Biobank and 23andMe who had taken a survey about various life behaviors, including whether they had engaged in a sexual experience with a person of the same sex at any point in their life.

About 26, individuals — or 5 percent of the subjects — fit this description, which is similar to the percentage reported across society more generally.

Think of all of humanity as consisting of 7 billion copies of the same book. All humans contain the same words — or individual genes — that make up how we think and how our organs function. But the words in our respective genetic books — or their code — look slightly different.

Some of my letters might be red, while some of yours are colored blue. This may sound counterintuitive, but those variations can also share similarities. The books that make up my family look similar to each other — in this example, they contain other shades of red. The technique can be used to suss out why certain people and their particular genetic variations correlate with health conditions like autism , physical traits like curly hair or colorblindness, behaviors like handedness or emotions like loneliness.

The strongest signals came from five random genes. Two of those genes correlated with same-sex sexuality in males, one of which is known to influence the sense of smell. One gene cropped up for females and two others showed solid patterns in both males and females. But their individual scores never passed this 1-percent mark — meaning they are all minor contributors to same-sex sexual behavior.

When the team looked more broadly across all the genomes — across the thousands of genes that they screened for the nearly , subjects — the genes similarities they found could only account for 8 to 25 percent of same-sex sexual behavior.

Firstly, what makes people think homosexuality is a choice in the first place? Most cite religious beliefs, although the notion that religion is flat-out opposed to homosexuality is far from accurate , and getting more uncertain as time progresses.

Old style prejudice and paranoia seem to be more involved here. You could also blame the media, and there may be some validity in this. And some people choose homosexuality. Presumably this is some time during adolescence when sexual maturity really kicks in, and you know what teenagers are like.

Is choosing homosexuality just another example of a desire to not conform , like shaving your head or wearing outlandish clothes? His study, which analysed the genomes of 40 pairs of gay brothers, looked exclusively at people who identified as homosexual. He sees the new paper as an analysis of risky behavior or openness to experience, noting that participants who engaged in at least one same-sex experience were also more likely to report having smoked marijuana and having more sexual partners overall.

Hamer says that the findings do not reveal any biological pathways for sexual orientation. Rice and Vilain agree that the conclusion is unclear. A more detailed questionnaire that looks at more aspects of sexuality and environmental influences would allow the researchers to better pinpoint the roots of attraction.

The authors say that they did see links between sexual orientation and sexual activity, but concede that the genetic links do not predict orientation.

Nevertheless, Hamer and others praise the new contribution to a field that suffers from a dearth of good studies. Sara Reardon is a freelance journalist based in Bozeman, Mont. She is a former staff reporter at Nature , New Scientist and Science and has a master's degree in molecular biology. Already a subscriber? Sign in.