Adult Child Behavior Child, Preschool DRD2 protein, human Female Follow-Up Studies Gene-Environment Interaction GxE Humans Infant Male Maternal Behavior Mother-Child Relations OXTR protein, human RSA Receptors, Dopamine D2 Receptors, Oxytocin Respiratory Sinus Arrhythmia Self-Control Young Adult adult child behavior dopamine 2 receptor female follow up genetics genotype environment interaction human infancy infant