Participants will be enrolled for approximately 12 to 30 months, depending on when they enter the study. Participants will have two screening study visits and then monthly visits. Monthly study visits may take place at a clinic, the participant's home, or other community site. Monthly visits will include a medical interview; urine testing, including pregnancy testing; HIV and sexually transmitted infection risk reduction counseling; and distribution of study supplies (condoms and gel-filled applicators). Blood collection will occur at selected monthly visits. Four times a year, participants will be seen in the clinic for a more structured medical interview, pelvic exam, and HIV testing. At one of these visits, participants at particular sites who are willing will be asked to complete a behavioral risk assessment. At some visits vaginal fluid swabs will occur. Participants at non-US study sites will be asked for permission for these swabs to be stored for further testing. Assessment interviews will be both face to face and self-reporting.