Most of the evidence about the causes of crime overlooks genetic transmission. Yet, some research has found that once you account for genetic influences on self-control, previously identified social transmission effects (read: parenting) on the child’s self-control become unstable. In other words, when you control for genetic transmission (the alternative explanation that most criminologists overlook), the effect of parenting on self-control diminishes or goes away entirely.

Consider another type of parenting effect — one that shows up in the news frequently — spanking. Not long ago, we examined the relationship between spanking and behavioral problems in children. Once we controlled for genetic transmission, there was no spanking effect in the way that most scholars think about spanking effects. Put another way, our evidence did not support the conclusion that spanking causes behavioral problems in the sense that most psychologists would argue.

The conundrum of heritability transcends parenting. For instance, it’s obvious that crime isn’t randomly distributed across neighborhoods. It seems to be a relatively stable factor that defines an area over many generations. Equally nonrandom, though, is the process by which people sort themselves into neighborhoods. People cluster into areas based on a host of factors, including the primary factor of income. Here’s the kicker, if any of the traits that affect residential choices are heritable and you ignore that influence, your findings regarding the impact of neighborhood factors on crime could be in jeopardy.