Mother-child conflict and sibling relatedness: A test of hypotheses from parent-offspring conflict theory

Parent-offspring conflict theory (POCT) has been underutilized in studies of human family dynamics. An implication of POCT is that the presence of siblings will increase conflict in biological parent-child dyads, and that half siblings will increase that conflict more than full siblings. Evidence consistent with this prediction was found in a longitudinal study of 236 early adolescent children and their mothers. Following parental disruption, the entry of younger maternal half siblings into the home was uniquely associated with elevated conflict between mothers and their biological children, independent of the effects of family size, socioeconomic status, and maternal depression. As predicted by the model, the effect of parental disruption on mother-child conflict was partially mediated by the entry of half siblings (but not stepfathers) into the home.