Risky families are characterized by conflict and aggression and by relationships that are cold, unsup- portive, and neglectful. These family characteristics create vulnerabilities and/or interact with genetically based vulnerabilities in offspring that produce disruptions in psychosocial functioning (specifically emotion processing and social competence), disruptions in stress-responsive biological regulatory sys- tems, including sympathetic-adrenomedullary and hypothalamic-pituitary-adrenocortical functioning, and poor health behaviors, especially substance abuse. This integrated biobehavioral profile leads to consequent accumulating risk for mental health disorders, major chronic diseases, and early mortality. We conclude that childhood family environments represent vital links for understanding mental and physical health across the life span. Good health begins early in life. In the first years of childhood, the family is charged with responsibilities for the care and devel- opment of the child. In healthy families, children learn that they can count on the environment to provide for their emotional security and their physical safety and well-being, and they acquire behaviors that will eventually allow them to maintain their own physical and emotional health independent of caregivers. From this vantage point, a healthy environment for a child is a safe environ- ment; it provides for a sense of emotional security and social integration and it offers certain critical social experiences that lead to the acquisition of behaviors that will eventually permit the child to engage in effective self-regulation (Basic Behavioral Science Task Force of the National Advisory Mental Health Council, 1996). Poor health also begins early in life. Research consistently suggests that families characterized by certain qualities have dam- aging outcomes for mental and physical health. These character- istics include overt family conflict, manifested in recurrent epi- sodes of anger and aggression, and deficient nurturing, especially family relationships that are cold, unsupportive, and neglectful. Families with these characteristics are risky because they leave their children vulnerable to a wide array of mental and physical health disorders. In this article, we propose a synthetic model of these links, focusing on the pathways through which risky families may not only hinder healthy development in childhood, but influ- ence physical and mental health into adolescence and adulthood. As indicated in Figure 1, risky family characteristics create a cascade of risk, beginning early in life. Families with these char- acteristics may create vulnerabilities and may exacerbate certain genetically based vulnerabilities, which not only put children at immediate risk for adverse outcomes (such as is the case with abuse), but lay the groundwork for long-term physical and mental health problems. Specifically, we will show that risky families create deficits in children's control of and expression of emotions and in social competence, and also lead to disturbances in physiologic and neuroendocrine system regulation that can have cumulative, long-term, adverse effects. We especially focus on disruptions in sympathetic-adrenomedullary (SAM) reactivity, hypothalamic-