Domestic Although the rate of breast-feeding is increasing in the United States, it appears that the rate of increase has been much slower among less well educated and economically disadvantaged women. Relatively little is known about the behavioral and attitudinal factors that affect the decisions to breast-feed or to stop if already breast-feeding. Breast-feeding does appear to decrease an infant's risk of gastrointestinal infection and otitis media. The effect of method of infant feeding on risk of other infections and allergic illness is less certain. International The rate of breast-feeding in developing countries appears to have declined, especially among urban women. Although some sociodemographic correlates of infant-feeding choice have been examined, little is known about the behavioral and attitudinal factors that influence choice and duration of infant-feeding practices. Milk insufficiency, maternal employment, and pregnancy frequently are given as reasons for terminating breast-feeding. Rates of gastrointestinal illness are lower among breast-fed infants and when such illness is an important cause of death, infant mortality from this cause appears to be reduced. A randomized clinical trial carried out among high-risk infants found a significantly lower rate of infections among those given breast milk than those fed with infant formula. The evidence of the effect of breast-feeding on respiratory tract and other infections from other studies was less clear. Direct comparison of the growth of predominately breast-fed v artificially fed infants in the same populations from developing countries generally show faster growth for the breast-fed infants for the first 6 months of life. After 6 months, severe growth faltering occurs regardless of the method of feeding. In communities where the nutritional adequacy of supplementary foods is poor, breast milk is an extremely important, high-quality food during the second half of infancy and beyond.