None of the three social class groupings is exclusively made up of white respondents; in fact, the racial/ethnic distribution is fairly consistent across the social groups. The only exceptions to this generalization are that the working-class and middle-class group includes a more substantial Hispanic population than does the professional middle-class group, and the few Asian respondents were all members of the professional middle class.
The groups do differ in other ways, as might be expected. Not only on average do the professional middle-class respondents have higher incomes than do those who are working class or middle class, but on average the professional middle-class respondents are also older than the middle-class and working — class respondents. The professional middle-class respondents were also older than their less privileged peers when they had their first child. Moreover, the professional middle-class respondents were least likely to have only one child and most likely to have the modal number of two children.