We are all born researchers. Behind this apparently conventional slogan, the idea is to recognise children’s capacity for reflection, analysis, curiosity, discovery and creativity. These capacities are certainly in a different state of development from those of adults, but they are just as relevant to be mobilised in an open and shared scientific research process. From a transdisciplinary perspective, this chapter describes the status of children as co-researchers participating in scientific questioning, in the development of methodological tools, the discussion of research results and in their valorisation. In a dynamic of co-production of knowledge, children as extra-academic actors are invited to participate in the research process and to bring their expertise to bear on issues that concern them directly. At the intersection of the fields of transdisciplinarity and childhood and children’s rights studies, we address the theoretical, methodological and ethical issues of research with children. The experience of a research project involving children serves as an example of application and lessons to be learned from a critical perspective. The benefits of children’s participation in research are highlighted, not only for the scientific community and society but also for themselves in terms of developing their capacity for reflection, expression as well as their research skills and scientific curiosity.