Abstract
Increases in cohabitation, nonmarital childbearing, and partnership dissolution have reshaped the family landscape in most Western countries. The United States shares many features of family change common elsewhere, although it is exceptional in its high degree of union instability. In this study, we use the Harmonized Histories to provide a rich, descriptive account of union instability among couples who have had a child together in the United States and several European countries. First, we compare within-country differences between cohabiting and married parents in education, prior family experiences, and age at first birth. Second, we estimate differences in the stability of cohabiting and married parents, paying attention to transitions into marriage among those cohabiting at birth. Finally, we explore the implications of differences in parents' characteristics for union instability and the magnitude of social class differences in union instability across countries. Although similar factors are associated with union instability across countries, some (prior childbearing, early childbearing) are by far more common in the United States, accounting in part for higher shares separating. The factors associated with union instability-lower education, prior childbearing, early childbearing-also tend to be more tightly packaged in the United States than elsewhere, suggesting greater inequality in resources for children.