Abstract
Men who father their first child at a very young age are convicted of significantly fewer crimes in the first years after birth if the child is a son rather than a daughter. This leads to behavioral spillovers that reduce criminal convictions among other young men living in the same neighborhood, with the resulting crime multipliers affecting peers’ crime even after the primary impact on the focal individual has dissipated. Through social multipliers, prevention policies that target potential criminals at an early stage, therefore, lead to larger reductions in the cost of crime than suggested by primary effects alone.