We kindly appreciate the chance to reply to Waligora’s1 comments on what we call personalized assent. Assent understood from an engagement point of view does justice to the specifics of childhood. In practice, this can be translated into personalized assent, which means that both the process and the content of the assent procedure are dynamic and adjusted to the individual child and research context.2

Waligora1 expresses two doubts concerning personalized assent. First, he argues that a positive relationship between children and their parents is assumed, as assent can provide protection against exploitation. Even if assent would offer some form of protection against exploitation by parents, we do not think that it alters our interpretation of assent. Assent from an engagement perspective gives rise to the moral obligation of the researcher to involve the child, which is aimed to respect the child and his/her (growing) capacities. Although parents or guardians have an indisputable role in the inclusion of children in research, assent is orientated towards the child. Even though a positive relationship between child and parent is desirable and helpful in engaging the child, it is not a requirement for assent. It is up to the researcher to assess what the role of the parent or guardian should be in the assent procedure in that particular situation.

Second, Waligora invites us to reflect on the practicality of personalized assent. He indicates that there is an alarming situation because of the variation in general organization of research ethics committees (RECs) in the European Union, and he argues that therefore personalized assent would be hard to fulfill. However, personalized assent allocates the responsibility to engage the child towards the researchers. Thus, even with a poor general organization of RECs, the researcher can obtain personalized assent. Waligora illustrates his claim with a study on Polish children, who participated in the Gabriel project, which is a project aimed to identify the genetic and environmental origin of asthma. In the study, 706 questionnaires from children between 6 and 14 years were collected about their participation in the Gabriel project. Overall, 42% of the children said they were not asked for their opinion on participation, whereas 39% of the children felt that both parents and children should be asked for permission and another 33% thought that children of their age should always give permission.3 This study is an excellent illustration of children who have, unfortunately, not been involved in the decision-making process and it underscores our notion of assent. We agree with Waligora that in order to foster and safeguard the engagement of children in the decision-making process, practical guidance is needed. Although an age limit seems attractive from a practical point of view, it entails the risk of working counterproductively. Instead of making sure that children are asked for assent, it may result in excluding children who want to and can be engaged but are not old enough. Moreover, what matters are the child’s capabilities, and although age can be a guide to this, other factors determine the actual development of capabilities,4 for example, life experience. In addition, it is important to note that personalized assent is not so much a legal but a moral concept.

Thus, an age limit will not be of assistance to achieve appropriate engagement of the child in the decision-making process. We must, however, be mindful that personalized assent does not become an empty concept. Guidance should be provided to researchers on how to implement personalized assent.