Document Type



Females survive males at most ages in virtually all modem industrialized societies. However, stratification of a sample by socioeconomic indicators shows that white infant male and female postneonatal mortality rates converge as the mothers’ or parents’ education rises and as the mothers age. These results are congruent with the parental selection hypothesis and with other findings that suggest that families at the pinnacle of the local social structure invest heavily in males and that parents nearing the end of their reproductive career try hard to effect the survival of all offspring.