1 a Population Studies and Training Center , Brown University , Providence , RI , USA.
2 b Department of Sociology and Social Anthropology , Stellenbosch University , Stellenbosch , South Africa.
3 c Department of Obstetrics, Gynecology & Reproductive Sciences, Bixby Center for Global Reproductive Health, and Center for AIDS Prevention Studies , University of California , San Francisco , CA , USA.
4 d Department of Global Health & Social Medicine , Harvard Medical School , Boston , MA , USA.
5 e Department of Medicine , Brigham and Women's Hospital , Boston , MA , USA.
6 f Department of Global Health and Development , London School of Hygiene and Tropical Medicine , London , UK.