“Non-traditional” siblings and the academic outcomes of adolescents

Using the National Longitudinal Study of Adolescent Health, this paper explores the extent to which residing in “non-traditional” sibling compositions (i.e., living with step- and/or half-siblings) explains the relationship between academic disadvantage and stepfamily living. Net of demographic and family background characteristics, “non-traditional” sibling compositions are associated with lower grades and higher levels of school-related behavior problems. The disadvantage associated with “non-traditional” siblings accumulates or remains constant over time as family members live together. Controlling for sibling composition mediates the lowered outcomes of youth in married stepfamilies and explains a portion of the disadvantage experienced by those in cohabiting stepfamilies. Thus, part of what makes stepfamily life detrimental to the academic outcomes of youth appears to be the complexity, ambiguity and stress that comes with having “non-traditional” siblings living within the same home. These results confirm the importance of considering the composition of a young person’s entire residential family unit, rather than focusing exclusively on the structure of parent–child relations, when studying adolescent academic outcomes.