On the possibility of the reemergence of a dysgenic trend with respect to intelligence in American fertility differentials.

The author "examines the relationship between IQ and fertility in a sample of men and women aged 25-34 as of the late 1970s. This sample is of unusual interest for two reasons: (1) it is a national probability sample, representative of the non-institutional civilian population of the U.S. as a whole, and (2) it is for a post-World War II cohort. Most previous studies of the IQ/fertility relationship have employed nationally unrepresentative samples of cohorts born in the pre-war period, 1910-1940. The bias, in both time and place, of the samples used in these studies has not been adequately grasped by those who cite them as evidence of a eugenic trend with respect to intelligence." It is hypothesized that persons with higher intelligence tend to have fertility equal to, if not exceeding, that of the population as a whole in periods of rising birth rates and that the opposite is true in periods of falling birth rates. This hypothesis is generally supported by the data set described above. Variations by sex and race are also examined. excerpt