The nature or nurture debate has been running through science, both biology and psychology, for over a century. This debate centers on the relative importance of an individual’s innate qualities (their “nature”) compared with an individual’s personal experiences (“nurture”). One of the reoccurring themes is whether people are born bad, or at least with the predilection towards certain anti-social or harmful behaviors.
Certain physical characteristics are biologically determined by genetic inheritance such as the color of one’s eyes or whether hair is curly or straight. Things get a little more complex when behaviors are drawn into the debate, especially when the concepts of “choice” and “free will” are questioned. In reality, things are probably more complex than the extreme nature or nurture positions that are sometimes taken.
One new study has looked at sexual offences, especially sexually aggressive behavior, and has concluded that the primary reason is genetic and that tendencies to commit sexual offences run in families. “Sexual offences” is a very broad term and different nations have different definitions as to what constitutes a sexual offence. Rape and violence with a sexual motive are, however, universally found throughout most justice systems.
The new study has been published in the International Journal of Epidemiology, in a paper called “Sexual offending runs in families: A 37-year nationwide study.”
With the study, researchers studied the population of Sweden over a long period of time (just under 40 years). During the course of the study, the behaviors of the participants were recorded and anything that might be considered a sexual offence highlighted. Here, some 21,566 men committed a sexual offence between the years 1973 and 2009. Of these, 6,131 involved the rape of an adult and 4,465 an offence against a child.
When the data was analyzed, both environmental and genetic factors were considered. The comparator that came out as most important was the sexual crime rate among fathers and brothers of sexual offenders when examined against the corresponding rates for fathers and brothers who had no sexual crime convictions. This analysis found a “strong familial aggregation of sexual crime” in that there was a one in five chance that a man who was brought up in a family where either their father or brother had committed a sexual offence, would himself commit a sexual offence.
The authors of the research do not discount environmental factors completely, but they have found that genetic factors are very important. The implications from these findings for policy makers are significant. Here it could be argued that prevention efforts should be orientated towards male first-degree relatives of sexually violent men since these are the most “at risk” individuals in the population.
These findings may or may not be supported by other studies and could be considered controversial by those who see upbringing or social conditions as equally or more important. Nevertheless, the findings do require pause for reflection and discussion.
