An improvement in prenatal care over several generations could enhance the birth weights of term infants. We reviewed data on live-born, singleton infants born at our university medical center between 1935 and 1985. Our review of 42,185 such pregnancies revealed that the mean birth weight (3,279 g) of a term infant has not changed significantly during the past 50 years. The frequency of term infants' weighing less than 2,500 g has not changed, but there has been a significant increase in the percentage of macrosomic infants (greater than 4,000 g), from 3 to 14, in the last 15 years. White infants have been consistently heavier than black infants, by an average of 179 g (6.3 oz). Differences in mean birth weights have been consistently greater for male than female infants (123 g, 4.6 oz) and for multiparous than primiparous deliveries (79 g, 2.8 oz), regardless of race. Impressions from these data, spanning three generations, should be helpful for prenatal counseling.