Wednesday, September 16, 2009

Study on Genes and Age of First Sexual Intercourse

The latest issue of Child Development has this interesting study which suggests that genetics plays an important role in explaining why children raised in homes without a father are more likely to have sex earlier than those raised in homes with a father. This study illustrates how complex the interaction between our environment and our biology really is, and how far we still have to go in terms of our understanding of the different things (like the genes we inherit from our parents) that influence human behaviour. Here is the abstract of the study:

Children raised without a biological father in the household have earlier average ages of first sexual intercourse than children raised in father-present households. Competing theoretical perspectives have attributed this either to effects of father absence on socialization and physical maturation or to nonrandom selection of children predisposed for early sexual intercourse into father-absent households. Genetically informative analyses of the children of sister dyads (N = 1,382, aged 14–21 years) support the selection hypothesis: This association seems attributable to confounded risks, most likely genetic in origin, which correlated both with likelihood of father absence and early sexual behavior. This holds implications for environmental theories of maturation and suggests that previous research may have inadvertently overestimated the role of family structure in reproductive maturation.

And here is a sample from the EurekAlert! on the study:

Previous research has found that children raised in homes without a biological father have sex earlier than children raised in traditional nuclear families. Now a new study that used a novel and complex design to investigate why this is so challenges a popular explanation of the reasons.

Among prior explanations of why children who live in homes without fathers have sex earlier are that early childhood stress accelerates children's physical development, that children who see their parents dating may start dating earlier, and that it's harder for a single parent to monitor and supervise children's activities and peers. All of these are environmental explanations.

"Our study found that the association between fathers' absence and children's sexuality is best explained by genetic influences, rather than by environmental theories alone," according to Jane Mendle, assistant professor of psychology at the University of Oregon, who led the study.