A validated population of male and female monkey breeders (M. Nemestrina) contains 84 animals at high or low risk for bad pregnancy outcomes. These include abortion, stillbirth, prematurity, low birth weight, and neonatal death. Offspring from high risk breeders exhibit anomalies in growth, feeding, diurnal cycles, abd aspects of learning, social behavior, and motivation. This breeder population and their offspring serves as an experimental model to (1) identify genetic, prenatal, perinatal, and postnatal factors which result in (2) offspring mortality, prematurity, and mental and social retardation or other disabilities, with the goal of (3) preventing bad pregnancy outcomes and their associated offspring abnormalities. To approach our goals, we conduct experiments with the following aims. (1) To identify specific factors causing abortions, prevent these abortions, and produce surviving offspring at high risk for developmental abnormalities; (2) to study effects of premature birth by delivering offspring from high and low risk parents by C-section at early gestational ages; (3) to study the unique contribution of males to bad pregnancy outcomes and offspring abnormalities by time mating breeders of opposite risk for bad pregnancy outcomes; (4) to identify interactive effects of risk, prenatal stress, perinatal condition, and rearing in enriched vs. impoverished environments; and (5) to assess effects of newborn condition on maternal behavior and mother-infant interaction during neonatal and infancy periods. Our final aim (6) is to relate chromosomal, physiological, anatomical and biochemical data to offspring abnormalities occurring in all studies.