The Consequences of Multi-partnered Fertility for Parental Involvement and Relationships

At the nexus of changing marital and fertility behavior is a new reality of contemporary family life—the fact that a significant fraction of adults today (will) have biological children by more than one partner, sometimes called ‘multi-partnered fertility.’ In this paper, we use data from the Fragile Families and Child Wellbeing Study to explore the consequences of multipartnered fertility for family relationships about three years after a baby’s birth. We find that earlier parental obligations are strongly linked to the focal couple’s relationship quality and their ability to co-parent effectively. Fathers’ having previous children is particularly deleterious—at least from mothers’ perspectives. We discuss the implications of our findings for family roles in childrearing, the organization of kin networks, and current public policies. Major changes in family demography in the past half century in the U.S. have undermined the longstanding link between marriage and childbearing that has historically prevailed throughout the Western World. Compared to their counterparts in previous cohorts, couples today often live in cohabiting unions prior to marriage and have a high likelihood of divorce and of subsequently living with or marrying a new partner (Bumpass, Raley, and Sweet 1995). Concurrent with these changes in marriage practices has been a sharp increase in childbearing outside of marriage—either before and/or after first marriage, or in the absence of marriage altogether. In 2005, the latest year for which data are available, fully 37 percent of all births occurred outside of marriage, with higher proportions among racial and ethnic minorities (Hamilton, Martin, and Ventura 2006). While the marriage and fertility trends noted above are by now well-known, at their intersection is the little-known fact that a non-trivial and rising fraction of adults have (or will have) biological children by more than one partner, a pattern which we refer to as ‘multipartnered fertility’ (and abbreviate as MPF). Estimates from a recent birth cohort study of urban parents suggest that for close to 40 percent of all couples who had a child together in the late 1990s (60 percent of unmarried couples and 24 percent of married couples), either the mother or father (or both) already had a previous child by another partner at the time of their common child’s birth (Carlson and Furstenberg 2006); this proportion will only increase over time as parents proceed through the remainder of their childbearing years. In a representative sample of American men, 16 percent of men ages 35-44 had children by two or more partners, and successive cohorts appear to be transitioning to multi-partnered fertility at even higher rates, suggesting that the overall prevalence is rising (Guzzo and Furstenberg 2006).