Early Genetic and Environmental Influences on Eating - The Baylor Infant Twins Study

4 months: observation of infant feeding behavior, behavior/temperament; bio-specimen collection; body composition, sucking intensity/frequency, activity intensity/frequency; maternal reports of feeding and behavior/temperament; maternal biospecimen. 6 month: behavior/temperament assessment, physical activity, and body composition. 12 month: Feeding behavior, behavior/temperament assessment, physical activity, and body composition. 24 month: maternal reports of children's eating behavior, behavior/temperament.