In recent years, research and practice on adverse childhood experiences (ACEs) have shifted from delineating effects of ACEs on adulthood health problems to preventing ACEs in children. Nonetheless, little attention has focused on how parents' own childhood experiences, adverse or positive, may influence the transmission of ACEs across generations. Children's risk for ACEs and potential for resilience may be linked to the early child-rearing experiences of their parents carried forward into parenting practices. Additionally, parents with multiple ACEs may have PTSD symptoms, an under-recognized mediator of risk in the intergenerational transmission of ACEs. Guided by developmental psychopathology and attachment theory with an emphasis on risk and resilience, we argue that a more comprehensive understanding of parents' childhood experiences is needed to inform prevention of ACEs in their children. Part I of this review applies risk and resilience concepts to pathways of intergenerational ACEs, highlighting parental PTSD symptoms as a key mediator, and promotive or protective processes that buffer children against intergenerational risk. Part II examines empirical findings indicating that parents' positive childhood experiences counteract intergenerational ACEs. Part III recommends clinically-sensitive screening of ACEs and positive childhood experiences in parents and children. Part IV addresses tertiary prevention strategies that mitigate intergenerational ACEs and promote positive parent-child relationships.