This article in the November issue of the journal Pediatrics identifies a link between viewing violent content and aggressive behavior. In particular, boys ages 2-4 who view violent video content or play violent videogames are predisposed to antisocial behavior evident five years later (ages 7-9).

Interestingly, there was virtually no correlation for the girls of the same age in this study. The researchers suggest that this could be attributed to the difference in socialization between genders.

Special thanks to avid reader David Stoddard for the info!