DRD4 and Anxiety: (1) to study gene-environment interaction of DRD4 polymorphisms and early caregiving on the longitudinal development of self-regulation capacities, (a) at the level of personality characteristics for self-regulation at age six and age 12 (ego-resiliency and ego-control), (b) individual differences in dysregulation at age six and age 12 (aggression and anxiety), and (c) behavior problems at age six and seven,