Introducing the

Objective: To describe the research design and sample of the Future of Families Third Generation (FFG3) study, which is collecting data on the third generation of the Future of Families and Child Wellbeing (FF) study. Background: Research on the intergenerational transmission of health and socioeconomic status (SES) has been limited by a paucity of prospective multigenerational studies with infant health in two generations. Method: The FFG3 study is enrolling children of the original 1998-2000 FF birth cohort, who are now young adults (second generation, G2), and collecting perinatal data and biological samples. We provide background, describe the research design and sample, and present data on 349 G2 mothers who had children by age 26 and 558 of their G3 children. We compare characteristics of this recent cohort to those of the previous generation of early childbearing mothers (G1) and their G2 children. Results: The recent cohort of mothers and their children born ~25 years after the original study began is much more disadvantaged than the original cohort. Physical and mental health of G2 mothers was worse than that of the G1s, as was the health of their infants. The proportion of marital births has not changed appreciably across generations (11% in FFG3, 12% in FF), but a much higher proportion of G2 mothers reported that the other parent was unknown (15%, versus 1%). Conclusion: The FFG3 study will facilitate novel and important analyses of intergenerational transmission of health and SES.