OBJECTIVES: Our aim was to assess the knowledge of 14–19-year-old adolescents about the types and symptoms of venereal diseases and how to recognize them, as well as student’s sexual education and behaviour.

METHODS: Our quantitative, cross-sectional study used a self-administered online questionnaire with non-probability accidental sampling method among secondary school students (N=126). Besides descriptive statistics, t test, ANOVA, correlation analysis and χ² test were calculated (p<0.05).

RESULTS: Professionals (of health care and education), media, and information from peers focuses on contraception, sexually transmitted diseases (STDs), sexual behaviour, while intimate hygiene and the importance of screenings are less preferred topics. On the contrary, all these topics are almost equally represented within families. Education provided by professionals had a positive effect on adolescents’ knowledge of how STDs are transmitted (p<0.05) but did not affect their knowledge of how to recognize them (p>0.05), symptoms (p>0.05), consequences (p>0.05) or their knowledge of contraceptive methods (p>0.05). A higher rating of the subjective perception on health care system had a positive effect on better knowledge of contraception (p<0.05). Knowledge of the urological screening process was positively associated with willingness to participate (p<0.05). Those living in the same household could influence young people's behaviour in seeking medical advice (p<0.05) but showed no association with greater knowledge of contraceptive methods (p>0.05).

CONCLUSIONS: Students' knowledge about STDs and contraception is insufficient. The perception of the health care system would be more positive if young people were better informed by professionals about the importance, the procedure and the need for screening. Family members encourage adolescents to visit a physician, but do not provide adequate information on contraceptive methods and the importance of screening. It is key to extend health education in schools, to involve parents into education, and to update and strengthen their knowledge.