With a long historical lens, the paper addresses questions of change and continuity within Swedish political and professional discourses on divorce and post-divorce parenthood during the 20th century, the century proclaimed as “the century of the child” by the Swedish reformer Ellen Key. As divorce became a legally viable option early in the century, also for families with minor children, the question of what constituted proper post-divorce parenthood and family life became a matter of social work expertise. With regards to divorce, new interpretations of concepts such as “the child’s best interest” and “family stability” begun to circulate among social workers and family counselors. The paper discusses these transformations, where earlier efforts to foster family stability and shared responsibility for children within a marriage, were substitutes with techniques of regulating family life and parenthood also after divorce and separation.