Are men more violent than women?

Article here. Excerpt:

'Steven F. Messner and Robert J. Sampson decided to take a closer look at the numbers behind the statistics of violence. They approached the issue by testing a simple hypothesis: If men are more violent than women, we should see more acts of violence in communities that have a larger male population compared to a female population. But their findings proved differently.

Messner and Sampson discovered that the rate of violent crime was higher in communities that had more females than males. This meant a larger percentage of men in these communities committed acts of violence than men in communities with a more balanced ratio of men to women. Why would that be?

They suggested a few ideas that might explain this trend. One is that in communities that have more women than men, there are more cases of disruption in families. That means that there are more single-parent families -- usually families with no father. Messner and Sampson suggest that the lack of a stable family environment contributes to a culture of crime and violence, though they say that other factors are also important.'