The effects of family background factors on the mobility aspirations of 70 black and white Chicago, Illinois male adolescents were investigated. Data on family socioeconomic status, family structure, parent aspirations for the son and parent-child relationships were obtained by interviewing the father, mother, and son in each family. Results indicate that although levels of aspiration do not differ by race, the determinants of these aspirations do. Among black adolescents, the mother was the most influential in the determination of aspirational levels, while among the whites it was the father. This finding is not to be construed as a negation of the other parent's role, however, since in both cases the overall parent effect on son's aspiration was positive. Parent aspirations for the son explains nearly half the variance in adolescent aspiration for both races. (Author/AM)