Family lives are an area where people's moral identities are crucially at stake. Yet the significance of dependent children to the work needed to sustain morally adequate adult identities is largely overlooked. Furthermore, the particular situation of divorce or separation and repartnering where children are involved is fundamentally relevant to current sociological debates about the changing nature of marriage and family life. Notions of the pursuit of self-development and couple intimacy clash and create tensions with notions of duty or responsibility to children's needs. Drawing on a study of parents and step-parents, we consider how interviewees' moral understandings were fundamentally shaped by social constructions of the Child and the Adult. Importantly, the presence of dependent children led to an overall key moral imperative concerning the requirement for responsible adults to put the needs of children first. There were, however, strong gender dimensions in the ways in which this moral imperative was played out, and in some tensions with an alternative, but secondary, moral ethic of care of self. We discuss the significance of the Child/Adult construction in relation to theories about the nature of contemporary family obligations and of contemporary morality more generally.