Race of parents and infant birthweight in the United States.

Detailed 1977 national natality data are used to investigate social, demographic, and genetic effects on birthweight differentials. Analysis of birthweight differences among infants with white, black, and mixed black-white parents indicates that a portion of the observed weight differentials appear to be due to biologic factors. Infants with a black mother and father have the lowest mean birthweights, while infants with two white parents have the highest weights. Newborns with mixed-race parents have intermediate birthweight distributions. Multivariate analysis suggests that the effects of parental race on birthweight are not the result of maternal/obstetric differences among parents of the same or mixed race.