Analysis of vital statistics for the Czech Republic between 1986 and 1993. including 3, 254 infant deaths from 350, 978 first births to married and single women who conceived at ages 18–29 years, revealed a neonatal survival advantage for low-weight infants born to disadvantaged (single, less educated) women, particularly for deaths from congenital anomalies. This advantage largely disappeared after the neonatal period. The same patterns have been observed for low-weight infants born to black women in the United States. Since the Czech Republic had an ethnically homogenous population, virtually universal prenatal care, and uniform institutional conditions for delivery. Czech results must be attributed to social rather than to biologic or medical circumstances. This strengthens the contention that in the United States, the black neonatal survival paradox may be due as much to race-related social stigmatization and consequent disadvantage as to any hypothesized hereditary influences on birth-weight-specific survival.