For the past decade, a research team based at Princeton and Columbia universities has been engaged in a national, long-term study of the consequences of childbearing outside marriage and has shared the resulting data and findings widely with the academic and policy-making communities. The Fragile Families and Child Wellbeing Study was supported by the Robert Wood Johnson Foundation (RWJF) from February 1, 1998 through December 31, 2011, and the study continues with support from other grants. Out-of-wedlock births increased dramatically in the latter decades of the 20th century, and the researchers sought to fill what they viewed as an information void about this growing group of at-risk parents and their children—what the team termed “fragile families.” The study conducted interviews with the parents of approximately 5,000 children born in 20 large U.S. cities at the turn of the 21st century and tracked these families through follow-up interviews when the children were one, three, five, and nine years old. Approximately three-quarters of the couples were unmarried at the time of birth; the married one-quarter served as a control group.