A new statistically reliable study refutes the notion of a single genetic marker or the so-called gay gene that determines a person’s sexual orientation.
According to Live Science, while scientists still expect complex and not-yet-understood genetic factors affect sexual orientation, they are certain that it’s not a single genetic on/off switch. The new study suggests that no individual gene alone makes a person gay, lesbian or bisexual but thousands of genes probably influence sexual orientation. The notion of a “gay gene” was first conceptualized due to a single 1993 experiment that was never replicated. Now for the first time, conclusive research completed via a massive experiment that succeeded by virtue of its sheer scale has put that theory to rest.
The paper about this experiment was published last Friday in the journal Science describes how twenty doctors from 21 research institutions joined forces with the genetic testing company 23andMe’s research team to analyze the genomes of 493,001 participants from the United States and Europe. They could not find anyone gene linked with same-sex sexual behavior while five genetic variants did seem to be significantly linked to sexual orientation, and thousands more also appeared to be involved to a lesser extent. The study concluded that sexual orientation is linked with a large number of genes, making it more likely to exist on a spectrum than a binary.
Andrea Ganna, the Harvard scientist who oversaw the project, told Live Science, “To give you a sense of the scale of the data, this is approximately 100-times-fold bigger than previous studies on this topic”.
Live Science reports that earlier experiments in this field were too small to make decisive conclusions. Also, their scope was limited by the difficulty of recruiting homosexual participants as same-sex relationships are still illegal in many parts of the world.