Children's resemblance to their biological and adopting parents in two ethnic groups

This study tested the hypothesis that adopted children's individual IQs are more related to the individual social status ranks of their biological parents than to those of their adopting parents. Data from 20 Mexican-American and 21 white biological and adopting families in which the IQ score of the adopted child was available show that (1) there was no significant selective placement of these children in adopting homes, (2) there was no significant correlation between the midparent social-education rank of the adopting parents and their adopted children's IQ, and (3) there was a strong correlation between the midparent social-education rank of the biological parents and their children's individual intelligence ranks.