The lecture will explore the degree to which early life, especially early family interactions, determine brain development. These individual differences in brain function then influence both cognitive function and health. Indeed the effects on cognitive development and health are closely inter-related. The lecture will focus on 1) studies with non-human subjects describing the effects of maternal care on gene expression, neuronal development and health in adulthood and 2) studies that examine these same themes in human populations, including the lecturer's own longitudinal studies of children. Finally, we will discuss the establishment of a new, longitudinal birth cohort study in Singapore examining the determinants of individual differences in cognition and health in Singaporean children (The Growing Up in Singapore Towards Healthy Outcomes - GUSTO - Project).