 HIV is an infection that damages a persons immune system and can develop into AIDS. More than 10 million women between the ages of 15 and 24 currently live with HIV or AIDS, most of them in sub-Saharan Africa and Asia. The rate of infections in women is high in part because they may not be able to use existing HIV prevention methods: remaining abstinent does not help if their partner is not also abstinent and using a male condom requires the compliance of the male. Oral and topical microbicides are products women initiate using to reduce their risk of HIV infection. Several clinical trials of these products have been conducted, but few have tested populations of young women, who may have different characteristics or behaviors from other women. This study will collect data on the characteristics and behaviors of women divided into two age groups, women age 15 to 17 and women age 18 to 21, in both Tanzania and India. This study will have four goals: 1 to determine whether and how characteristics that put women at risk for HIV differ in these age and country groups; 2 to evaluate the legal, social, cultural, and delivery factors that hinder womens participation in microbicide trials; 3 to examine the understanding and ability of women in these different groups to adhere to the requirements of clinical trial participation; and 4 to determine young womens acceptability and use of a practice gel or pill. 