Sex education has been a requirement in Swedish schools for the past 30 years. The purpose of the study was to describe the opinions of 17- and 18-year-old Swedish students at the upper secondary school regarding the sex education they received at school as well as their knowledge about the anatomy and physiology of reproduction. A questionnaire concerning education about sex and relationships was answered by 421 students. The results of questions regarding human reproduction illustrated that the students have insufficient knowledge about men's and women's reproductive organs. Two-thirds of the students who had received sex education thought the instructions were insufficient. The students wanted to talk more about positive and negative feelings within a relationship and feelings concerning sexually transmitted diseases and abortion. In summary, the results indicated that the content of sex education should focus on women's reproductive organs and the feelings and relationships between men and women. The type of instructions and how instruction time is utilized should be examined closely.