Using data from a recent longitudinal study of a single high school graduating class, the authors examine the relationship between parenthood and sex role attitudes and aspirations. They find that parents are more traditional than nonparents, partly because parents were more traditional prior to having a child. Controlling on earlier traditional-egalitarian orientations, the transition to parenthood exerts effects that vary by the color and marital status of the respondent. For white married respondents, becoming a parent has a clear and traditionalizing influence. For unwed black women, the opposite effect is observed — parenthood leads to more egalitarian attitudes. The authors interpret this pattern to reflect costs and benefits of traditional sex roles to different groups under different situations.