Relationship Instability, Multiple-Partner Fertility, and the Complexity of Household Obligations

Laura M. Tach, University of Pennsylvania

Recent research has revealed a great deal of relationship instability and multiple-partner fertility among unmarried parents. These processes result in complex social and biological family ties within and across households. In this paper, I document the prevalence of complex family forms that result from relationship instability and multiple-partner fertility for a cohort of nonmarital children born during the late 1990s, using data from the Fragile Families and Child Wellbeing Study. I then compare the economic and interpersonal relationships across family types and show how such relationships change after mothers and fathers transition into new partner and parenting roles. Using fixed and random effects regression models, I find that both parental relationship quality and fathers’ economic contributions decline after mothers and fathers enter new romantic relationships and have new children. These findings suggest that at least part of the association between family complexity and household economic and interpersonal relationships is causal.