Number of siblings and educational attainment.

Family background continues to be closely related to individuals' educational attainment in the United States. A notable change in one aspect of this background, number of siblings, is occurring as fertility is becoming extremely low. Examination of the negative relation between individuals' sibling number and years of schooling indicates that education among those with many siblings is disproportionately cut short before high school graduation. Because there is a strong negative relation between number of siblings and scores on tests measuring verbal ability, recent reductions in sibling number would be expected to contribute to enhanced verbal ability and increasing years of schooling for those born now in the United States.