Newborn brain weight in relation to maturity, sex, and race

Fresh brain weight, gestational age, body weight, sex, and race were collected from autopsy records of 782 newborns over a 10-year period. The brain weight of the mature newborn does not differ between males and females or between white and black infants. For the premature, however, brain weight is heavier in white males than in black males and in white females than in black females. These differences are similar to those found for adults in our previous studies, and they correspond to differences in gestational age and body weight in the subgroups. The differences in brain weight between races are best explained on the basis of environmental factors.