The purpose was to investigate the sexual behaviour among young men (n = 300), visiting a genitourinary clinic in Sweden, focusing on the impact of pornography. Almost all, 98% (n = 292) claimed to be heterosexual. The mean age at first intercourse was 16 years and on that occasion 64% (n = 187) used some kind of contraceptive, mainly condom. All, 99% (n = 296) had consumed pornography and 53% (n = 157) felt that pornography impacted their sexual behaviour; they got inspired. About half (n = 161) had had anal intercourse. Of these, 70% (n = 113) had had it more than once and 84% (n = 133) could imagine doing it again. Only 17% (n = 28) always used a condom in this situation. One out of four (n = 70) had had at least one sexually transmitted disease. The low use of condoms when heterosexual men have anal sex might have serious consequences for a spread of sexually transmitted diseases.