London - The age when we lose our virginity could be down to something as simple as hair colour.
Men and women who are natural redheads are more likely to delay their first sexual encounter than those of a different hair colour. Women – but not men – with freckles are also more likely to wait longer.
According to a scientific study, genetics plays a surprising role in helping determine sexual behaviour including how many partners we have.
The same DNA factors predicted which people were more likely to be older when they have their first sexual experience, the timing of the birth of their first child or even if they were more likely to be childless.
Gene variations affecting hair colour were among 38 found to have an influence by acting on the timing of physical maturity and by contributing to differences in personality types. A risk-taking gene called CADM2 makes certain people more likely to have sex, at an earlier age, and with more partners. People with genes linked to being irritable, called MSRA, were likely to first have sex at an older age than average. But if irritability makes them unattractive, it may also have a benefit. Fruit flies with the same gene also delay reproduction, but live longer.
The study published in Nature Genetics looked at links between genetic characteristics and sexual behaviour in 380 000 people worldwide including 130 000 Britons.
It is hoped that a better understanding of sexual behaviour could lead to improvements in public health. The timing of a person’s first sexual experience and the birth of their first child is linked to performance in school, and health factors including diabetes, heart disease and breast cancer.
Researchers from the Medical Research Council (MRC) and Cambridge University looked at genetics in sexual behaviour as other factors such as economic disadvantage and family instability have received more attention in the past. Hair colour and freckles are affected by a gene called MC1R.
The report states: “Genetically predicted skin freckling seemed to promote later AFS (adult first sexual experience) in women but not in men and genetically predicted red hair seemed to promote later AFS in both men and women.”
The study found that the overall average age of the first sexual experience was 18, and the birth of the first child was 25.
Dr John Perry, a geneticist at the MRC Epidemiology Unit and lead author, estimated that the effect of DNA on sexual behaviour was around 25 percent – with social and cultural factors behind the other 75 percent.
He said: “With all human diseases and complex traits, any individual gene has a small effect. It’s a sum of many, many genes. It’s not like there’s a gene that’s going to make you have sex on May 23, 2016.”
But he said that genes may speed up or slow down the time someone first has sex by weeks.
Of the CADM2 gene, Dr Perry said: “It changes our perception of risk. It’s probably manifesting in all sorts of ways, but the most obvious is the number of sexual partners.”
Daily Mail