This paper studies how socioeconomic attainments of parents in intact two-parent families, non-residential parents, single parents, and parents in stepfamilies affect children's attainments. In doing so, we draw together two lines of research: one on the inheritance of social status that consistently reports that children benefit from greater maternal and paternal resources, and another on family instability that argues that parental separation is associated with children's lower socioeconomic achievement in adulthood. The analyses are based on Finnish Census Panel data and sibling models, and socioeconomic statuses are measured by occupation-based ISEI scores. The results suggest that in terms of socioeconomic inheritance, fathers are replaceable: the influence of a non-residential father was very weak and was compensated by the strengthened effect of the single mother and by the further strong influence of a stepfather. The socioeconomic status of non-residential mothers and stepmothers contributed very little to a child's status. The socioeconomic attainments of children who had lived in single-parent families were lower than those of children who had been raised in intact two-parent families, but the differences were modest and varied with parental status. In absolute terms, the outcomes were poorest for children who lived with a low-status single parent, but the loss associated with parental separation was greatest for those who had high-status non-residential fathers. The total family background effect, measured as sibling similarities in socioeconomic attainment, was weaker in single-mother families than in other family types.