Effect on vaginal male-to-female transmission of HIV/Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT). Randomized to 6% CS gel or Placebo gel; both arms receive condoms and safer sex counseling. Any curable sexually transmitted infection (STI) or urinary tract infection (UTI) will be treated. Referrals for other conditions. Three monthly gynecological exam with STI testing.