After World War II, many American GI's (both white and black) fathered children by German women; these children were then raised in German society. The children fathered by black GI's had an average IQ of 96.5, and the children fathered by white GI's had an average IQ of 97 -- a statistically insignificant difference.
Another study measured the IQ's of children from black-white unions. Assuming that mothers are more important than fathers in the education and socialization of their children, the study sought to see if a child's IQ is higher when the white partner is the mother. This turned out to be true -- the IQ of a racially mixed child averages 9 points higher when it is the mother who is white.
The study includes data from birth to age 5 on 800 black and white children who were born premature and with a low birth weight. Collected from eight health care sites around the country, it is the only data set that combines high-quality measurement of developmental outcomes (i.e., full-scale IQ tests) with longitudinal data on family economic status, neighborhood conditions, family structure and home environment. Because the study looks at very young children, the subjects' IQ measures cannot be attributed to such non-family influences as schooling or work.
The study also takes into account how impoverished neighborhood conditions and environmental influences can affect even children not living in poverty. Black families are more likely to live in poor neighborhoods, whether or not they are poor themselves. "Almost one half of all black children whose families were not poor resided in poor neighborhoods, compared with less than 10 percent of white children," said Duncan.