Optimistic perception of HIV/AIDS, unprotected sex and implications for prevention among men who have sex with men, São Paulo, Brazil.

Background: This study examines the association between optimistic perceptions about AIDS and unprotected sex among men who have sex with men (MSM) in the city of São Paulo, Brazil.

Methods: A cross-sectional study was carried out among MSM in leisure areas of São Paulo in 2003. We interviewed 161 participants aged 18-30 years.