Current educational resources for sex education in Hong Kong are mainly designed to be used in classroom. They are mostly text-based and are unattractive to the most vulnerable adolescent group. As discussion on sex is still taboo in Chinese society, self-learning resources can supplement classroom teaching. This paper describes an interactive game playable on Facebook, iPad and the web to educate young adolescents with reliable knowledge and positive attitudes towards relationship and sex and life skills necessary for making wise decisions regarding love and sex in a fun way. The effectiveness and acceptance of the game were evaluated by more than 1000 grades 7-9 students from six schools. The results showed that after playing the game, students' sex knowledge improved with a medium effect size. The students were mostly receptive to the game, finding it fun to play with and describing the content as "interesting", "interactive", "informative", "close to reality" and "applicable."