Over the past four decades, income inequality has increased and family structures have diversified. We argue that family structure has become an important mechanism for the reproduction of class, race, and gender inequalities. We review studies of income inequality and family structure changes and find a wide range of estimates of the correlation. We discuss how increases in income inequality may lead to increases in single motherhood, particularly among less educated women. Single motherhood in turn decreases intergenerational economic mobility by affecting children's material resources and the parenting they experience. Because of the unequal distribution of family structure by race and the negative effects of single motherhood, family structure changes exacerbate racial inequalities. Gender inequalities also increase as mothers incur more child-related costs and fewer fathers experience family life with children.