To help predict physical, mental, and social behavior problems in school age children, this longitudinal study intended to identify the origins of dysfunction and the characteristics which put infants at high risk for future problems. The study provided background data for the development of an operational screening and assessment method. The mothers surveyed were primaparous and were receiving medical care during the pregnancy. Data were collected during the eighth month of pregnancy and five times within the infant's first year, from 193 mother-infant pairs. The following assessment methods were used: mother questionnaire, father questionnaire, mother interview, observation of environment, observation of parent-child interaction, developmental testing, and pediatric examination. Four mediating predictor variables formed a conceptual framework for the study: infant characteristics, infant's environment, parental perceptions, and mother's life change. An Optimal Parent-Infant Profile was presented as a compilation of information identified as being important during pregnancy and the first year of life. The Profile included variables related to the mother and family, psychosocial support, life change, parents' developmental expectations, mother's health, mother's perception of the infant, infant's health and sleeping behavior, mother-infant interaction, and home environment. Results clearly indicate the parents' major role in shaping the child's behavior. However, the ultimate goal of predicting high risk children can only be realized when data are collected beyond the age of one year. (CP)