Number of Siblings and Mental Health Among Adolescents: Evidence From the U.S. and China

A growing number of children are being raised with few or no siblings yet the consequences of this seismic demographic shift in family forms are not well understood. We investigate this question in the U.S. and China because previous studies highlight how contextual features can play an important role shaping how siblings matter. Our Chinese analyses draw on more than 9,400 eighth graders from the China Education Panel Study (CEPS). In the U.S., we analyze over 9,100 American eighth graders from the Early Childhood Longitudinal Study—Kindergarten Cohort of 1998 (ECLS-K:98), where our data allow us to consider multiple features of the sibship structure (e.g., size, sex composition, and density). We find that number of siblings is negatively associated with mental health in both China and the U.S., although the details of this pattern (non-linear association, sisters versus brothers, and closely versus widely spaced siblings) vary.