ABSTRACT In the United States, nearly half of pregnancies are unintended, and unintended pregnancies occur five times more often among poor women compared to affluent women. The proposed project investigates how providing access to free contraceptives impacts unintended pregnancy and, ultimately, the lives of children—both children whose births are unintended and their older siblings who may lose resources (both material resources and time) as a result of a mother’s unintended pregnancy. The proposed project significantly expands the scope of Michigan Contraceptive Access, Research, and Evaluation Study (M-CARES), a large-scale, randomized control trial that provides no-cost access to any type of contraception and tracks women longitudinally in surveys and rich, administrative data. The proposed project aims to: (1). Double the M-CARES recruitment period and increase the sample of children born before the intervention that are in the study by 1,000; (2). Develop and field two survey supplements (year 2 and year 4 post enrollment) of M-CARES participants to ask about (a) intendedness of each birth (pre- and post-intervention), (b) time and money spent on each child, (c) parenting practices, and (d) children’s health, schooling, extra- curricular activities, behavior and well-being; (3). Compile comprehensive longitudinal data using surveys (aim 2) and administrative records to document the outcomes of the children of M-CARES participants in (a) the short-term (5-year study period) and (b) long-term (until children reach age 18); and (4). Evaluate the causal effects of mothers’ access to free contraception on children’s outcomes in survey data (aims 2a-d) and administrative records (3a), including heterogeneity analyses by income, race, and education. Achieving these aims will contribute to social science and public health policy by providing novel experimental evidence on the understudied, intergenerational effects of making contraception free to women within the existing U.S. public health system. This study will, therefore, contribute to a larger cost-benefit analysis of a feasible and easy to implement reproductive health intervention—an intervention that potentially helps break the cycle of poverty and improve children’s life-time opportunities.