Abstract
Employing data from two Chicago-based household probability samples of men who have sex with men (MSM) implemented 5 years apart (the "UMHS 1997" and the "2002 MSM supplement" studies), we evaluated changes in risk behavior as well as the potential viability of two alternative perspectives for explaining these changes--risk management and safe-sex norm abandonment. We found significantly increased rates of unprotected insertive and receptive anal intercourse in the 2002 study. Sixty-eight percent of UMHS men reported having sex with partners having HIV positive or unknown status, compared with 38% of the MSM supplement men (p < .0001). Serosorting mediated and moderated the most extreme forms of risk behavior. Positive statistical associations between drug use and unprotected sex were stronger in the UMHS sample than in the MSM supplement. Findings suggesting that "risk management" strategies have shaped MSM behavior as it emerged in the early part of this decade have considerable implications for HIV prevention strategies.