When including adolescents/adolescents in a clinical trial, there are many ethical questions and complex implications such as the possibility of pregnancy in minors and the contraceptive measures to be used depending on their physical and psychological development. The psychological and ethical challenges are addressed in this guidance document published by swissethics and SwissPedNet. The document was written by a joint working group and is aimed at researchers, sponsors and others that conduct clinical research with adolescents. It is intended to provide help and support for the practical implementation, i.e. to counsel the adolescents and their parents in this particular situation. In addition to numerous references, the document provides a practical approach to dealing with these situations.