by Aislinn McDonagh
A large study using data from men and women from Iceland and the UK biobank has linked the age people lose their virginity to 38 specific genetic regions.
Unsurprisingly, many of these genes are linked to other factors. Genes associated with ADHD were strongly linked with having sex younger, and genetic areas influencing schizophrenia were also significantly negatively correlated with age of first sex, whereas genes related to intelligence had the opposite effect. Irritability also has an associated gene, MSRA, which was suggested to relate to later age of first sex. Correlations between genes which indicate likelihood of smoking and the age of first sex were also found. It is also bad news for redheads, as ginger hair was found to be associated with later first sex for both men and women, though freckles only affected women in the same way.
Unsurprisingly, a major factor focused on in this study was genes associated with risk-taking. CADM2 is a gene that is associated with numerous traits, including: risk taking; neuronal development; affects propensity of developing schizophrenia or bipolar disorder; and was found to have a significant relationship with age of first sex through neurobehavioral influence. All neurobehavioural factors were categorised in the study as stimulus seeking (risk taking), which lowered the likely age of first sex, and moderating traits such as intelligence and irritability, which raised it. Risk taking is also itself moderated by executive functions in the frontal cortex of the brain which control decision making and impulse control, hence the influence of intelligence.
Thought this study may seem sensational, it is not the first time such genetic links have been investigated. CADM2 has also been linked to a higher number of sexual partners, and other genes related to risk taking or novelty seeking have been similarly identified. The gene DRD4 has long also been associated with such behaviours, and like CADM2 has also been linked to ADHD and low attention, as well as sexual behaviours. Another study by Garcia et al. in 2010, showed via questionnaires that people who had the DRD4 gene had twice as great promiscuity rates (measured in one night stands), and were more likely to be unfaithful in relationships.
The less ‘bloggable’ but more concerning aspects of this study are those which link early puberty with age of first sex. Early puberty (often a sign of poverty due to childhood obesity, and not necessarily linked to reproductive fitness) is also linked causally with early first birth and lower educational attainment. Other established correlates of younger age of first sex include social disadvantage and family instability. This is not to imply that all those who have sex young are impoverished or to be pitied, but does indicate that early sex may not always be a sign of personality, maturity, or genetics, but due to other socio-economic and biological factors which limit the potential of young people.