For good reason, social scientists have a long history of being suspicious of biological explanations of human behavior. Importantly, however, recent paradigmatic shifts in the life sciences have largely obviated these longstanding concerns. We highlight the changes that have occurred in genetics with its movement away from genetic determinism to an emphasis on epigenetics and in neuroscience with its switch from a fixed to a neuroplastic view of the brain. We describe these new developments noting the way they recognize, indeed place a premium upon, the role of the environment. The remainder of the paper focuses upon the challenges and opportunities for social scientists, especially those involved in developmental work, proffered by these paradigmatic shifts. The evidence clearly shows that nature and nurture are inextricably interlinked. Importantly, however, it also indicates that they are connected in a manner that honors the priority that the social sciences place upon the environment. We contend that incorporating biological processes into our developmental work will sharpen our theories and enhance their significance. We argue that such biologically integrated models will provide a clearer and more comprehensive understanding of how nurture influences behavior across the life course.