Evolutionary psychologists claim that stepparents perpetrate substantially more child physical abuse than genetic parents, and that they do so because they are less invested in genetically unrelated children. The objective of this study was to examine these claims by investigating whether, and why, fathers in a Colombian sample physically abused their stepchildren more than their genetic children. Fathers (N = 86) and their partners living in Bogotá were interviewed by Klevens et al. Half of the fathers had been reported to authorities for child physical abuse, the other half were matched controls. Secondary analysis was conducted of Klevens et al.'s data. Hypotheses from the evolutionary and ecological accounts of child maltreatment were tested using logistic and ordinal regression. Both the prevalence and the frequency of physical abuse by stepfathers were considerably greater than those of genetic fathers. Several indicators of adversity-including parental youth and experience of abuse, fathers' chronic stress, and mothers' poor communication with the child-were associated with both abuse and stepparenthood. Models including these variables indicated that they accounted for much of the stepfathers' higher rates of abuse. Consistent with the ecological account, much of the stepfathers' greater prevalence and frequency of abuse in this sample is likely to have resulted from confounding variables, rather than from the step relationship per se.
Keywords: child physical abuse; evolutionary psychology; intergenerational transmission; stepfathers; stressors.