1. Department of Sociology and Office of Population Research, Princeton University, Princeton, New Jersey, USA
2. Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University, New Haven, Connecticut, USA
3. Department of Social Work, University of New Hampshire, Durham, New Hampshire, USA
4. Department of Health Management and Policy, University of Michigan, Ann Arbor, Michigan, USA
5. Institute for Social Research, University of Michigan, Ann Arbor, Michigan, USA