Summary Families influence their children's health in two ways that are amenable to public policy--through their financial and other investments in children, and through the quality of care that they provide. In general, children who receive more resources or better parenting are healthier than those who don't. Public policies, therefore, might improve children's health either by giving families more resources or by helping parents provide better care. When it comes to financial resources, write Lawrence Berger and Sarah Font, the research is straightforward--programs that add to disadvantaged families' incomes, whether in cash or in kind, can indeed improve their children's health. The Earned Income Tax Credit, for example, has been linked to higher birth weights and greater cognitive achievement. When it comes to programs that target quality of care, however, the picture is more complex. At the low end of the spectrum, poor parenting shades into neglect or abuse, which can seriously harm children's health and development. Thus we might expect that the child protective services system, which has the power to intervene and protect children in such cases, could also improve children's health in the long run. But Berger and Font find that the system's ability to affect children's health is limited, largely because it becomes involved in children's lives only after damage has already occurred. Other programs, however, have the potential to improve parenting, reduce maltreatment, and thus enhance children's health and development. Home visiting programs show particular promise, as do large-scale, community-level primary prevention programs. ********** Childhood health is associated with a wide variety of outcomes throughout the life course, from ongoing physical and mental health to disability, mortality, and socioeconomic status. Families bear the primary responsibility for making direct investments in children, as well as for regulating and allotting other public and private investments. That is, families provide the caregiving context in which most children grow and develop; they also provide and allocate resources to children. In this way, families play the primary role in promoting child health and development. Thus, any effort to promote child health must necessarily involve families. Yet the quality of the family environments in which children are raised varies considerably; in particular, not all families provide safe, stable, and high-quality care. In this article, we first explain how families are believed to influence children's health. In particular, we focus on family context (structure, composition, and access to resources) and parenting behaviors. We consider health in a broad sense, including physical, social-emotional, behavioral, cognitive, and mental health and development. Second, we describe the role of the child protective services (CPS) system in protecting children from familial harm and intervening with families where child maltreatment has occurred. We conclude that CPS has limited ability to influence child health, because it primarily intervenes only after harm has occurred and because a combination of resource constraints and a relatively narrow mandate means that CPS focuses on only a small proportion of children and families. Third, we review other policies and programs that can influence family contexts and behaviors before harm has occurred. We highlight several promising programs--including economic support, community-level interventions, and home visiting programs--that have the potential to improve the quality of care children receive, reduce child maltreatment, and positively influence child health and development. How Do Families Influence Child Health? Families are thought to influence child health through three primary mechanisms: biological and genetic endowments, financial investments (goods and services purchased), and behavioral investments (caregiving quantity and quality). …