Some differential attributes of lethal assaults on small children by stepfathers versus genetic fathers

Killings of children less than five years of age by stepfathers versus (putative) genetic fathers are compared on the basis of Canadian and British national archives of homicides. In addition to previously reported differences in gross rates, the two categories of killings differed in their attributes. Beatings constituted a relatively large proportion of steppaternal homicides, whereas genetic fathers were relatively likely to shoot or asphyxiate their victims. A substantial proportion of killings by genetic fathers, but almost none of those by stepfathers, were accompanied by suicide and/or uxoricide. These contrasts lend support to the hypothesis that the differential risks incurred by children in different household types reflect the differential parental solicitude that is predictable from an evolutionary model of parental motivation.