From 1969-77, a landmark longitudinal study of growth and development was carried out with support from NIH in four Guatemalan villages. This effort demonstrated, through nutrition interventions, that malnutrition has detrimental effects on the physical growth and mental development of young children. In 1988-89, when the former subjects of this study were adolescents and young adults (age range 10-26 yrs.), a team of investigators, also with support from NIH, carried out a cross-sectional study aimed at identifying the long-term repercussions of malnutrition in early childhood. The broad hypothesis tested was that better nutrition in early childhood leads to improved human capital as measured by larger body size, greater work capacity and improved intellectual functioning and school achievement. Though the analyses are still in progress, there is clear support for the notion that investments in nutrition in early life lead to young people with a greater potential for leading healthy, productive lives. A return to the villages to carry out a longitudinal study of the offspring of the women who participated, as young children, in the 1969- 77 longitudinal study is proposed. This ambitious effort will ling mothers and children of the original study, who are now grandmothers and mothers, with the current generation of children. The major hypothesis guiding the proposed research is as follows: Malnutrition and developmental impairment in early childhood constrains the future capacity of women to bear healthy newborns and the ability to care for them and, thus, the growth and development of the next generation. A five-year study made up of a short preparatory phase, 3 1/2 years of data collection, and 11 months for final analyses is proposed. A longitudinal study from birth to 36 months is planned. The target sample will be all children born to mothers living in the villages who participated in the 1969-77 study. Data collection includes maternal body composition, lactational performance, birthweight and newborn status, physical growth and maturation, child health and nutrition, cognitive assessments in adults and children, maternal-child behaviors, and socio-educational aspects. At the end of the study, over 400 mother- child pairs will be available for analysis at any age of interest. This will provide adequate power to identify effects of substantive importance. The study will be the most comprehensive assessment to date of the repercussions of malnutrition in early childhood across generations and the first to take place in a developing country. The data set to be obtained will be a valuable resource for researchers and students at the participating institutions. Feasibility for the project is very high. Most of the methods proposed have already been developed and used in the villages. The investigators are experienced in the design, implementation and analysis of longitudinal studies and among them, cover the required range of expertise. Finally, the investigators have successfully implemented a pilot study in the villages.