It has long been known that peer pressure and upbringing play a huge part in determining the age at which you first have sex. However, recent research shows that genes, too, play a very important role in the matter.
A study revealed that DNA accounts for one quarter of difference in the ages at which people first had sex; the other factors are religious beliefs, family background, and peer pressure.
John Perry, an expert in reproductive ageing and related health conditions at Cambridge University, said:
“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%, so one quarter nature, three quarters nurture.”
A version of the genes, CADM2, linked early sex with greater risk taking behavior and having more children. While a version of MSRA gene linked late sex with irritability.
The study was conducted on the DNA of more than 125,000 people aged 40 to 69, who enrolled in the UK BioBank project. Most men and women lost their virginity at 18. The study then did a comparative analysis on a further 250,000 people in the US and Iceland.
Early puberty (usually brought on by poor nutrition and childhood obesity) leads to having sex earlier, and also to having children earlier and having more children (as a result of the early start).
Earlier, attaining puberty early was linked to poor educational performance. However, it was argued that poor performance was just a reflection of other underlying factors, like poverty. With this study, scientists have now come closer to proving that early puberty is not a reflection but a cause of poor educational achievement.
George Davey Smith, a clinical epidemiologist at Bristol University, said:
“It suggests that earlier puberty does influence early age of sexual debut, which then appears to have other consequences such as, all things being equal, earlier first birth, having more children, less likely to remain childless, and poorer educational outcomes.”
There were 38 strands of DNA that were found to affect the age at which a person first has sex; these were the genes that drive reproductive biology (the release of sex hormones), and affect behavior, personality and looks.