In recent years, there has been increased attention for the position of adolescents and young adults in the justice system. The Netherlands implemented the Act on Adolescent Criminal Law in 2014, making it possible to sentence young adults up to the age of 23 at the time of the offence as juveniles. This article addresses the most recent Dutch reforms in order to identify key challenges to consider when accommodating young adults in the justice system. It is aimed to highlight the important lessons to be learned from the Dutch experience with a flexible approach to sentencing adolescents and young adults.

In this article a critical reflection upon age limits applied in the law is provided, in light of the tension that exists in international children's rights law between the protection of children and the recognition of their evolving autonomy. The main research question that will be addressed is to what extent the use of (certain) age limits is justified under international children's rights law. The complexity of applying open norms and theoretically underdeveloped concepts as laid down in the UN Convention on the Rights of the Child, related to the development and evolving capacities of children as rights holders, will be demonstrated. The UN Committee on the Rights of the Child struggles to provide comprehensive guidance to states regarding the manner in which the dynamic legal position of children should be applied in practice. The inconsistent application of age limits that govern the involvement of children in judicial procedures provides states leeway in granting children autonomy, potentially leading to the establishment of age limits based on inappropriate-practically, politically or ideologically motivated-grounds.

In recent decades, there has been increased attention to scientific evidence on the development of children and adolescents, and the implications this should have for the criminal justice system. This chapter explores a developmental approach to children who have committed serious violent offences. It does so by looking at the influence of scientific insights at the national level exemplified by the case law of the US Supreme Court that challenged punitive sentencing practices for children convicted of serious offences, and by discussing the developmental approach at the international level, in instruments of international children's rights law. The chapter determines that the rights of children with neurodisabilities is an important outstanding issue for the further evolution of the developmental approach within the framework of international law. Finally, a conclusion is drawn with respect to the growing recognition of a developmental approach and the contribution thereof to criminal justice responses to serious offences committed by children.