As fertility and mortality rates fall and the institution of marriage is redefined, the composition and structure of families have undergone radical transformations around the globe. In Canada, Quebec is a global leader in the rates of cohabitation, while legislative changes in British Columbia could make Canada the first western country to legalize polygamous marriages. Changes in family structures are no less profound in developing countries, where changing social norms and rising education levels for women are not only delaying their age of first marriage, but also shifting the marriage process from arranged marriages to autonomous unions, where spouses choose each other. In this research axis, CPD members are exploring how families have changed both over time and around the globe. We are particularly interested in examining how these changes affect each family member’s health, wealth, and happiness, and which types of family structures are most conducive to building strong societies.