RESUMEN
Most sexual education programs traditionally focused on providing sexual information regarding the risks of sex. However, current studies on sexual behavior in youth show a need for truly comprehensive sex education approaches with a sex-positive focus on sexuality, that effectively improve sexual competence. Therefore, in the current study the effectiveness of "Love is ", a four lesson school-based program based on the Sexual Interactional Competence model and Attitude-Social-Influence-Self-Efficacy-model was studied. A cluster-randomized controlled trial on the effectiveness of "Love is " was conducted in 2018-2020. The sample consisted of 1160 adolescents in grades 8 and 9 from nine schools in the Netherlands. The sample was 48% female, 34% Dutch/Caucasian, 41% none-religious and 50% higher educated. They were randomized at class level into a program group [n = 32 classes; 567 students (Mage = 13.74 (SD = 0.74))] and a control group [n = 31 classes; 593 students (Mage = 13.86 (SD = 0.73))]. Results showed that "Love is " increased sexual knowledge, that adolescents in the program group showed less cyber victim blaming attitudes and increased in communications skills after the program. In conclusion, the current study shows that "Love is " was effective not only on the knowledge level, but also regarding sexual attitudes and competences. However, due to the developmental process of sexuality, there is a necessity to continue lessons in following grades through booster sessions by reinforcing competences as communicating comfortably about sexuality.On 12 November 2019 the study design and hypotheses were registered in the Dutch Trial Registration, number NL8150. ( https://onderzoekmetmensen.nl/nl/trial/26676 ).