1Research Center for Medical Sociology, Tsinghua University, Beijing, China

2Department of Public Health and Primary Care, International Centre for Reproductive Health, Ghent University, Gent, Belgium

3Women and Children’s Health Information Center, Guangzhou Women and Children’s Medical Center, Guangzhou, China

4Amsterdam Law School, University of Amsterdam, Amsterdam, The Netherlands

5School of Public Health, Jackson State University, Jackson, MS, USA

6School of Public Health, Université Libre de Bruxelles, Bruxelles, Belgium

Jun Zhang, Research Center for Medical Sociology, Tsinghua University, Beijing 100084, China. Email: [email protected]Wei-Hong Zhang, International Centre for Reproductive Health, Department of Public Health and Primary Care, Ghent University, Gent 9000, Belgium. Email: [email protected]