Comparing Children's Behavior Problems in Biological Married, Biological Cohabitating, and Stepmother Families in the UK.

A large body of research shows that children who live with two married biological parents have lower levels of externalizing and internalizing behavior problems compared to their peers in other family structure, including cohabitating biological families. Such patterns suggest that marriage provides a uniquely protective family environment, though we know less about children in the obvious counterfactual case: married stepfamilies. While research suggests children with stepfathers have more behavior problems than those living with married biological parents, we know little about how children with stepmothers fare, or how children with stepparents fare compared to those living with cohabiting biological parents. We use the Millennium Cohort Study (MCS) sweep 6 to compare children living with married biological parents, married fathers and stepmothers, and cohabiting biological parents. We find that family structure has no significant relationship with children's internalizing behavior problems, but that children living with a stepmother and biological cohabitating families exhibit more externalizing behavior problems than do those living with married biological parents. Covariates that indicate both physical and social family environments must be considered together to explain differences in married-parent families on externalizing behavior problems.