Study claims genes may influence age at which girls lose virginity

A study published in the journal Child Development suggests that a father's absence may not be a causal factor in a child's earlier sexual maturation, but rather other factors such as the social environment and genetics.

It is already known that children raised in household without a father are more likely to engage in sexual activity at an earlier age and become teenage parents. However, underlying reasons for this are unclear: it could be that ‘father absence' has a direct effect on the children, or that father absence is a marker for other influences.

The research team, headed by Professor Jane Mendle at the University of Oregon, investigated the association using data collected for the US National Longitudinal Survey of Youth. The team compared 1382 offspring born to women who were twins, sisters or cousins. The mothers were interviewed annually between 1979 and 1994, and every two years thereafter. The children were also interviewed when they reached 14 years of age.

The team found that the more closely related the children were, the more similar their age at first intercourse, regardless of father absence. One explanation for this could be that genes which increase the likelihood of early sexual activity are also more likely to make a man abscond.

Professor Mendle states: ‘While there's clearly no such thing as a "father absence gene", there are genetic contributions to traits in both mothers and fathers that increase the likelihood of earlier sexual behaviour in their children.

‘These include impulsivity, substance use and abuse, argumentativeness, and sensation seeking. These traits get passed down from parents to children, resulting in a situation known as "passive gene-environment correlation", because the same genetic factors that influence when children first have intercourse also affect the likelihood of their growing up in a home without a father'.

Environmental factors could also account for the study observations: more closely related children are more likely to share similar social environments, for example their mothers may pass on similar attitudes and values. So although the study suggests that father absence may not be a main causal factor in early sexual maturation, it cannot discriminate conclusively between genetic and other factors, or how these two types of influences may interact.