Your Genes May Determine When You Lose Your Virginity

A new study suggests genetics may help determine when in life a person becomes sexually active. Christian Hartmann/REUTERS

It's well-known that genetics are linked to the age of puberty's onset, but a new study finds genes may also influence when in life a person becomes sexually active and has children. Even more interesting, these genetic markers are associated with distinct personality traits.

For the study, published April 18 in Nature Genetics, researchers analyzed UK Biobank data from more than 125,000 people, aged 40 to 69. The data included information on each patient's genetics and personal health history, such as the age of a girl's first period, education level, number of offspring and when the person first had sex. They identified 38 gene variants that appear to influence the age at which a person loses virginity.

The researchers were surprised to find that not all of these genes were also linked to puberty. One of the genes, CADM2, is associated with risk-taking behavior, while another, MSRA, is linked to irritability, according to the researchers. These findings suggest the gene variants don't directly cause a person to have sex earlier in life. Instead, these genetic traits may predispose the person to certain behaviors that would lead to sexual activity at a younger age.

Through a more extensive statistical analysis, the researchers also determined that these genetic variants were more common in people who had kids at an earlier age. Some of the same genes also appeared to be linked to lower education attainment, which makes sense, according to Dr. John Perry, a geneticist at the University of Cambridge and lead author on the study. "If you're maturing sexually ahead of your peers, you're going to be spending more time chasing girls or boys than working, and your priorities change and your behaviors change," Perry told Scientific American.

This is not to say that environment and lifestyle don't figure into the equation. Peer pressure, family upbringing, religion and popular culture all play a role in a person's sexual development. In addition, some environmental triggers are known to cause precocious puberty, an alarming trend in which puberty begins before age 8 in girls and before 9 in boys. For example, experts believe environmental pollutants such as Bisphenol A can disrupt a child's endocrine functions. Medical conditions such as diabetes and obesity can also accelerate sexual development.

In the beginning of the 20th century, the average girl in the U.S. had her first period at 16 or 17, but the average is now 13 or younger, according to data from the National Institutes of Health.