1. a International Centre for Reproductive Health (ICRH) , Mombasa , Kenya
2. b HIV and AIDS Program , Population Council , Nairobi , Kenya
3. c International Centre for Reproductive Health, Faculty of Medicine and Health Sciences , Ghent University , Ghent , Belgium
4. d Reproductive Health and HIV Research Unit , University of Witwatersrand , Johannesburg , South Africa
5. e Family Health International , Research Triangle Park , Arlington , USA