The anterior descending coronary artery was obtained from each of 160 subjects aged 2 to 30 years who died suddenly. The arteries were examined for early atheromatous changes and the mothers were asked about the way the children had been fed during early infancy. No evidence was found for the hypothesis that breast feeding confers protection against coronary artery disease. The mothers' smoking history at the time of the birth bore no relationship to the pathological findings in the arteries. It therefore seems unlikely that the type of feeding in infancy, or maternal smoking during pregnancy, are factors influencing the risk of coronary disease.