Using a subsample of emerging adults from the Stepfamily Experiences Project (n = 989), we examine how parents' repartnering choices (nonmarital and premarital cohabitation) influence their emerging adult children's commitment-related relationship attitudes (attitudes about sex in committed relationships) and behaviors (hooking up). We further examine these processes at the intersection of race and gender. In this way, we expand the current emerging adult literature by exploring two understudied populations: emerging adults who grew up in stepfamilies, and emerging adults from diverse racial backgrounds. We divided our sample by race (black, Latino, American Indian, white, and multiracial) and gender, resulting in 10 groups. We compared those 10 groups using structural equation modeling within the Bayesian framework. We found a strong association for all groups between attitudes about sex in committed relationships and hooking up and a connection between parental cohabitation and hooking up, which connection was only explained by attitudes for white men. We also found significant variation at the intersection of race and gender for all but one of our hypothesized associations. These results highlight the importance of examining variation at the intersection of race and gender and also suggest that family of origin factors, such as parental cohabitation, may impact hooking up among emerging adults raised in stepfamilies.