An Empirical Test of a Possible Solution to “the Central Theoretical Problem of Human Sociobiology”*

KANAZAWA (2004) suggests that there is a negative association between social class and reproduction because lower-class individuals, who tend to have lower general intelligence, have greater difficulty employing evolutionarily-novel modern contraception. I derive three hypotheses from KANAZAWA’s theory: 1) There are no class differences in the number of desired children; 2) The effect of sexual activity on reproduction is weaker among the more intelligent; and 3) The interaction between sexual activity and intelligence is stronger among men. The analyses of the U.S. General Social Surveys support all three hypotheses.