How Your Genetics Influence When You Lose Your Virginity

A new study has shown that genes influence your life in more ways than you think—and that includes at what age you lost your virginity.

While we're all pretty much au fait with the idea that genetics determines physical attributes like hair color, height, and weight, researchers have now discovered that they also play a part in determining when you first have sex, as well as the age when you have your first child.

The study, published in Nature Genetics on Monday, identified 38 sections of DNA that are linked to these significant moments in life—previously thought to be determined by choice, personal timing, and whether or not somebody remembers to pull out.

Researchers from the University of Cambridge and the Medical Research Council (MRC) analyzed the genetic data of 59,357 men and 66,310 women aged between 40 and 69 years old who were enrolled in the UK Biobank project. The team of scientists verified their findings by looking at data from 262,097 additional people from the US and Iceland.

They found that a gene called CADM2, which controls brain activity and brain cell connections, is associated with leading to a greater likelihood of being at a younger age when it came to losing one's virginity. The gene is also linked to an increased likelihood of risk-taking behavior.

"We were able to calculate for the first time that there is a heritable component to age at first sex, and the heritability is about 25 percent, so one quarter nature, three quarters nurture," lead study author John Perry told the Guardian.

CADM2, along with another called ESR1, is also linked to the number of children that a woman has over her lifetime. The MSRA gene was found to be associated with an irritable temperament, and—maybe not too surprisingly—researchers discovered that people with the gene were more likely to lose their virginity at an older than average age.

"A lot of the associations that we're showing, with the sort of personality that might have an impact on when people first have sex, are entirely plausible," said Felix Day, a University of Cambridge scientist who worked on the study. "It's not unreasonable to say that those people who are more likely to take risks are more likely to have sex at an earlier age. But I think the novelty on this is that there is a genetic influence on that causal pathway."

Day also said that the team of scientists found the gene that led women to be more likely to punch their V-card at an earlier age had a "very visible effect" on later life outcomes—they were also more likely to give birth to their first child at an earlier age.

Men and women who lost their virginity earlier were also more likely to have fewer years in education, though Day cautioned that this data came from people who were born between the 30s and late 60s: "It's perfectly possible that the societal and educational situation about early sexual activity for those generations is quite different to what it is now."

Unexpectedly, redheads—men and women alike—were discovered to be more likely to lose their virginity at an older age than their brunette or blond counterparts. Women with freckles were also more likely to have sex for the first time at a later age—though the same did not apply to their male counterparts.

Day declined to theorize on why freckled girls popped their cherry later, saying that he did not want to speculate. But he cautioned against worrying that your genes, for better or worse, have already determined everything about your sex life.

"What this [research] is saying is not that somewhere in your genes is encoded a date that you will lose your virginity, but rather that this explains people to be more likely to have it earlier or more likely to have it later. And earlier and later might be in relevance to different ages based on the societal and environmental factors, like social environment, peer pressure, and parental pressure.

"One thing to highlight there is that we are only explaining about 25 percent of the variability. For someone who studies genetics like I do, 25 percent is quite an excitingly large number! But it also means that 75 percent of the variability is left unexplained by genetics."