Data-driven health informatics technologies such as mobile health apps and wearable and smart medical devices have become ubiquitous in people's daily lives. As these technologies advance and become more pervasive, the datafication of personal health research has grown substantially in recent years. The field is however primarily focused on adult users, leaving a limited understanding of children's data practices and technology for managing their health and well-being. In this work, the authors aim to delve deeper into children's health datafication practices, navigating the landscape of their technology use, caregiver involvement, and the distinct factors associated with their development and literacy. The authors’ intention is to catalyze future innovations, improving the design and utility of health technologies tailored for children.The authors present an overview of the history of personal health datafication research, child development theories, and child-computer interaction studies. This work contributes to the literature by characterizing the trends in children's health datafication research, reflecting on key research themes to guide future health datafication research focused on children, and by providing recommendations for future research and design of data-driven technologies that support children's health and wellbeing.