The Nonmarital Childbearing Network is an international group of researchers organized to study the development of nonmarital childbearing and family change more generally. Over the past several decades, nonmarital childbearing has increased dramatically in Europe, Australia, and the U.S., and yet few studies outside of the United States have focused on this issue. In order to examine how and why nonmarital childbearing has increased, this project will study the trends and correlates of nonmarital childbearing from a number of analytic levels and methodological perspectives. The project aims to: advance our understanding of the development of nonmarital childbearing in diverse contexts; contribute to debates on the underlying causes of this increase; employ innovative statistical techniques to analyze and classify patterns across countries; and develop a new theoretical framework for understanding the diffusion of family change. Using a unique database of comparative nationally representative surveys, the project will provide insights into the reasons why women give birth within different types of partnerships: cohabiting or marital, or as single mothers.