Because parental childcare time has an important influence on child development, class- based disparities in maternal and paternal childcare time may contribute to inequality in child outcomes. Theory suggests that class gaps in family structure and class-based assortative mating may widen class gaps in total parental childcare time, while specialization between partners may reduce these gaps. Yet, these hypotheses have not been rigorously tested. We match parental respondents within the American Time Use Survey to generate synthetic parental dyads, which we use to estimate, in turn, the contributions of family structure, assortative mating, and specialization to class gaps in total parental childcare time. We find that class gaps in family structure lead to wider income-based gaps in total parental childcare time than observed in maternal or paternal time. Additionally, assortative mating widens education- and income- based gaps in total parental childcare time. However, specialization does not offset these wider class divides. (Author abstract)