An assessment of some proposed exceptions to the phenomenon of nepotistic discrimination against stepchildren

Stepparents commit child abuse and homicide at much higher rates than genetic parents. Proposed exceptions, including a recent claim that there is no such "Cinderella effect" in Swedish homicides, are shown to be mistaken. The hypothesis that only "mothers' boyfriends" abuse children excessively, whereas married stepfathers do not, is tested and rejected in an analysis of Canadian homicides. De facto marriage and steprelationship are …