This article seeks to bring the invisible child of personalized medicine out from the shadows through legal analysis and empirical data. It uses Denmark as a case to argue that existing policies, laws and practices on personalized medicine neglect the legal and ethical issues specific to children. The article investigates Danish laws and practices in clinical genetics and describes how the law neglects children’s right to self-determination in three ways. Firstly, while child participation is provided for by law, no guidelines have been created to operationalize this norm. Secondly, children’s right not to know is inadequately reflected in current policies. Thirdly, the storage of information from prenatal genetic sequencing raises important issues that are in need of reflection. Several recommendations are made, including for strengthening children’s participation and limiting parents’ access to secondary findings where they relate to untreatable or unpreventable conditions. It furthermore recognizes, however, that children’s self-determination in some circumstances should be viewed relationally due to the interconnected nature of genetics.