We will soon launch our Third Generation–Babies (3GB) study. The 3GB study will examine neurobehavioral development, including brain structure and functioning, in the infants of twin parents from the Minnesota Center for Twin and Family Research (MCTFR). We will also examine family and environmental factors that may be associated with infant development, including parental stress and psychopathology, the parent-child relationship, and home and neighborhood risk and protective factors. This will be the first (to our knowledge) imaging study of infants of twins.