The purpose of this study was to characterize the risk of human immuno
deficiency virus (HIV) infection for men who have sex with men and to
identify the risk such men pose to their female sex partners. The subj
ects were 5480 men who were tested for HIV between January 1987 and De
cember 1991 and who reported having had sex with a man since 1977. Men
who identified themselves as bisexual or straight were more likely to
use injection drugs, had a substantial HIV seroprevalence, and report
ed many more female partners than men who identified themselves as gay
. Men who identify themselves as bisexual pose the greatest risk to th
eir female partners.