When becoming parents for the first time, German couples often adapt their division of paid and unpaid work, creating a more gender-specific allocation. Using longitudinal data from the qualitative event-centered project “Household division of domestic labor as a process”, we compare theoretically- postulated mechanisms of change in the division of work within couples with explanations given by the couples interviewed themselves. Our qualitative analysis demonstrates that economic and gender norm theories are quite successful at predicting changes towards a more traditional specialization when couples become parents for the first time, while they are less helpful in explaining the persistence of equal arrangements in the domestic division of work, or the change towards more equal arrangements. The interviews also show that the explanations which differentiate – within unpaid work – between childcare and housework are a better predictor of the realities of the arrangements. Furthermore, the causal order of the decisions suggested by the theories differs from the couples’ actual decision making processes: when facing the transition to parenthood, they decide first upon the division of childcare, and then of labor market activity and housework.