Although considerable progress in the treatment of patients with AIDS has b
een achieved over the recent years, AIDS remains a non-curative disease. Th
erefore the prevention of new infections with HIV is an important goal for
medicine and public health. However, during recent years the number of new
HIV-infections in young gay men increased. New empirical data from the U.S.
and the U.K, suggest that the traditional prevention methods fail to reach
young gay men in Western countries who become HIV-infected by unsafe sex w
ithin intimate relationships. The paper discusses these problems from the p
erspective of medical ethics. New approaches to sex education and preventio
n of HIV and other sexually transmitted diseases are developed and the impo
rtance of personal values, responsibility, intimacy and emotions are emphas
ized.