105 of the the German Jugendgerichtsgesetz (JGG, law on criminal cases involving offenders between 14 and 17 years of age) allows the use of this special law also for offenders between 18 and 21 years of age if they can be considered juveniles with regard to their personal development or the type of crime they have committed. Assessment of the "maturity" of young people in this age group has been the subject of great controversy in forensic psychiatry since the first JGG went into effect in 1953. In spite of numerous attempts to operationalize the term "Jugendlicher", for example in the Marburg guidelines, it has not yet been possible to establish clear-cut criteria defining the characteristics of those who are juveniles in the sense of the JGG. Neither child and adolescent psychiatry nor criminal law nor criminology has provided an adequate basis for such a definition. The wide range of discretionary decisions in forensic psychiatry and the associated lack of legal uniformity may, however, be a necessary prerequisite for an adequate assessment of an individual case. Although the chances of a change in criminal law governing those between 18 and 21 are small, creation of a law specifically for this age group, with a separation of the educational-therapeutic aspects from the punishment aspects, could be a great help to those preparing expert opinions in forensic psychiatry and to the juvenile courts because it would necessitate greater clarity in decisions relating to this group of offenders. Elimination of Section 105 JGG and the subsequent use of either general criminal law or that governing those under age 18 only, which has been proposed repeatedly, is not recommended.