Black and Mexican-American men have higher verbal IQs than the women? Looking at GSS data, I see that the mean Wordsum score for Mexican Americans born here is 5.70 for men and 5.44 for women (N = 173). There is also a slight advantage for black men born in the country over black women (4.93 versus 4.86, N = 2,961). This reverses the sex pattern seen among whites (6.21 for men and 6.38 for women born in the U.S., N = 16,236). The differences are small (only the white gap is statistically significant) but, still, it's weird.
It's not due to education since Mex-Am and black women stay in school longer than their male counterparts. And it's not work. NAM women work more hours per week than white women, and the work gender gap (men of all three groups work more) is smaller among NAMs. What's the explanation? Just a fluke?
UPDATE: It looks like there is an explanation for blacks, anyway. Only 37% of the black sample is male. The GSS does not sample institutionalized or homeless people, and as the reader suggests, more low-IQ black men may refuse to participate in the survey.
But this doesn't seem to explain Mexican-American men who make up as much of the Mex-Am sample as do white men the white sample--45.8% and 44.5%, respectively.
Wanting to take another look, I used ETHNIC instead of HISPANIC to identify Mexican Americans because ETHNIC has been asked many more years. Yielding a sample of 393 people born in the U.S., the male Wordsum mean is 5.07, and for females it is 4.82. (HISPANIC produces a much higher average than ETHNIC because Mex-Am scores have been on the rise for the past 20-30 years--thank God). The male advantage is still there for the larger sample, but again it fails to reach statistical significance.