A representative group of young persons (N=745), who used the youth clubs in Copenhagen were asked to fill in a structured questionnaire. A large group of the young had had their sexual debut (N=367). In respect of this group we found no correlation between prevention regarding geneeral health risk factors vs. prevention against HIV contraction. It is discussed as to whether this difference can be accepted as an expression of the fact that adolescents do not consider the risk of AIDS as something that can affect them. Similarly, current problems in the chain of knowledge, attitude and behaviour in relation to intervention programmes are also discussed, including ethical aspects.