Article by Vandepitte J, Lyerla R, Dallabetta G,Crabbé F, Alary M, and Buvé A in Sex Transm Infect. 2006 June; 82(Suppl 3: iii18–iii25. This research attempted to estimate the number of women in the world that sell sex by collating information from published and unpublished literature, as well as from field investigators involved in research or interventions targeted at female sex workers. The proportion of women in adult female populations was calculated including by were extrapolating subnational estimates to national estimates.