Congruence between mothers' and fathers' differential treatment of siblings: links with family relations and children's well-being.

We studied patterns of mothers' and fathers' differential treatment of firstborn (average age 10.5 years) and secondborn (average age 8 years) school-age siblings, and we examined the links between parents' differential treatment and children's well-being and dyadic family relationships. Mothers, fathers, and both siblings in 110 families were interviewed in their homes. For each dimension of parental behavior that we assessed (i.e., differential affection and discipline) we created groups of families that reflected mothers' and fathers' levels of differential treatment (e.g., discipline the firstborn more, equal treatment, discipline the secondborn more). Although we detected substantial correspondence between the 2 parents' differential treatment, we found a sizable group of families in which parents' reports were incongruent (i.e., 1 parent reported equal and the other differential treatment). Parental patterns were linked to differences between the siblings' well-being and both sibling and parent-child relationships, with younger siblings exhibiting greater vulnerability to differential treatment. Incongruence in differential warmth was associated with marital distress.