Spurred by Parapundit's Randall Parker and the sight of low-hanging stereotype-validation fruit, the estimated IQ scores (converted from GSS wordsum results with the simplifying assumptions of a mean population IQ of 100 and that one standard deviation in wordsum results is the equivalent of 15 IQ points) of men and women who have procreated at least once, by marital status, follows. For utility, all data are from 2000 onward and the foreign-born and those aged 46 and older are excluded.
Married -- 101.0
Divorced/separated -- 97.8
Unmarried -- 93.6
Married -- 101.3
Divorced/separated -- 98.7
Unmarried women -- 93.6
Parenthetically, the mean IQ for those of the same age and time cohort who haven't had any kids is 101.2. To see dysgenic forces in action, look no further than single mothers and their unfortunate spawn, who have both the nature and nurture decks stacked against them.
GSS variables used: CHILDS(0)(1-8), BORN(1), WORDSUM, YEAR(2000-2012), SEX, MARITAL(1)(3-4)(5), AGE(18-45)