We use data from three waves of the Fragile Families Study (N= 2,111) to examine the prevalence and effects of mothers’ partnership changes between birth and age 3 on children’s behavior. We find that children born to unmarried and minority parents experience significantly more partnership changes than children born to parents who are married or White. Each transition is associated with a modest increase in behavioral problems, but a significant number of children experience 3 or more transitions. The association between instability and behavior is mediated by maternal stress and lower quality mothering. The findings imply that policies aimed at reducing maternal stress and partnership instability may improve child well‐being.

We draw on three waves of the Fragile Families Study (N ¼ 2,249) to examine family stability among a recent birth cohort of children. We find that children born to cohabiting versus married parents have over five times the risk of experiencing their parents' separation. This difference in union stability is greatest for White children, as compared with Black or Mexican American children. For White children, differences in parents' education levels, paternal substance abuse, and prior marriage and children account for the higher instability faced by those born to cohabiting parents, whereas differences in union stability are not fully explained among Black and Mexican American children. These findings have implications for policies aimed at promoting family stability and reducing inequality.

This paper uses data from the Fragile Families and Child Wellbeing Study to examine whether family instability is associated with changes in perceived social support, material hardship, maternal depression, and parenting stress among mothers of young children. In addition to accounting for the number of transitions a mother experiences over the first five years of her child’s life, we pay close attention to the type and timing of these transitions. We find that mothers who transition to cohabitation or marriage with their child’s biological father experience declines in material hardship and that those who transition to cohabitation or marriage with another man exhibit modest declines in both material hardship and depression. Mothers who exit cohabiting or marital relationships encounter decreases in perceived social support and increases in material hardship, depression, and parenting stress. Overall, our results suggest that both the type and, to a much lesser degree, the timing of family structure transitions may influence maternal well-being.

This paper uses data from the Fragile Families and Child Wellbeing Study (N = 2,098) to examine differences in the parenting practices of four types of resident fathers, defined by their biological relationship to a focal child and their marital status with regard to the focal child’s mother. Regression results suggest that biological and social (i.e., stepfathers or mothers’ cohabiting partners) fathers differ significantly, and in some unexpected ways, on most measures of parenting. However, a considerable portion of these differences can be explained by variation in the background characteristics of the individuals and families in each group. Additionally, difference-in-difference analyses reveal a stronger link between marriage and higher quality parenting practices among social fathers than among biological fathers.

Trends in family formation during the past several decades have increased children’s exposure to mothers’ partnership instability, defined as an entrance into or exit from a coresidential union or a dating partnership. Instability, in turn, is associated with negative outcomes for children and adolescents. This study uses data from the Fragile Families and Child Wellbeing Study to examine associations between mothers’ partnership instability and children’s school readiness, differences between coresidential and dating transitions, and the moderating role of child gender. Mothers’ partnership transitions are negatively associated with children’s verbal ability and positively associated with boys’ behavioral problems at age five. In general, coresidential and dating transitions have similar effects on school readiness. The findings have important implications for our understanding of the growing gender gap in educational attainment.