BACKGROUND: Sweden has the highest abortion numbers among the Nordic countries. Since 1995, the abortion rate among teenagers has increased by nearly 50%. We therefore undertook a study where the overall aim was to gain a deeper understanding on which factors female teenagers believe may explain the increasing numbers of teenage abortions. Teenagers' perceptions of teenage pregnancy, abortion, sexual behavior, and contraceptive habits were investigated. METHODS: Six focus group interviews with 17-year-old Swedish girls were conducted. The interviews were tape-recorded, transcribed verbatim, and analyzed by manifest content analysis. RESULTS: Negative attitudes toward teenage pregnancy and supportive attitudes toward abortion were expressed. Risk-taking behaviors such as negligence in contraceptive use and intercourse under the influence of alcohol were suggested as main reasons behind the increasing numbers of abortions among Swedish teenagers. The contemporary, sexualized, media picture was believed to influence adolescents' sexual behavior, and liberal attitudes toward casual sex were expressed. Girls were perceived as more obliged than boys in taking responsibility for contraceptive compliance and avoidance of pregnancy. The apprehension that hormonal contraceptives cause negative side-effects was widely spread, and the participants were found to have a somewhat limited knowledge of abortion. The majority were unsatisfied with the quality of sexual education provided by the schools. CONCLUSION: Possible reasons for increased abortion numbers among teenagers in Sweden could be liberal attitudes toward casual sex in combination with negligence in contraceptive use, use of alcohol followed by sexual risk-taking, fear of hormonal contraceptives, and a deterioration of sexual education in the schools.