Environmental influences on safer sex in young gay men: a situational presentation approach to measuring influences on sexual health.

Environmental influences on sexual behavior are difficult to examine given their temporal distance from the sexual act and the cost of long-term longitudinal studies. We examined environmental influences on risky sexual behavior in young gay men using the Situational Presentation (Sitpres) methodology, where situations in which relevant environmental variables are presented as computer vignettes with the variables randomly allocated, and participants rate the likelihood of their engaging in unsafe sexual behavior. A total of 100 gay men aged between 18 and 26 years of age completed 20 situational presentations with the outcome being the likelihood of engaging in unprotected anal intercourse. On regression analysis, 3 environmental variables significantly predicted safer sex: perceived gay/bisexual men's norms toward condom use; availability of HIV prevention messages; and what one's religion says about gay sex. Not significant were family, media, legal, and work/school attitudes to homosexuality. Demographic variables that were predictors included education, age, sexual orientation, and degree of being "out" about sexual orientation. These data suggest that environmental factors can be approximated using the Sitpres methodology, and that more proximal environmental variables have a stronger impact than distal ones.