Klaus Hurrelmann also calls for parents and professional childcare and teaching personnel to cooperate intensively in negotiating their different childrearing concepts. He bases this approach on a “Magical childrearing triangle” with the three poles “Recognition”, “Encouragement”, and “Guidance”. He also supports compulsory parent training and favors the introduction of a symbolic “parenting license.” Klaus Hurrelmann's work in health research focuses on the interface between the sociology of health and health education. He has taken a leading role in this field. His definition of health has been very influential: “Health denotes the state of well-being in individuals when their mental and social situation matches their potentials and goals within the specifically given external living conditions.” Health is accordingly the state of balance between risk and protective factors that emerges when an individual succeeds in mastering both internal (bodily and mental) and external (social and material) demands. It grants the individual well-being and vitality. This definition is now being viewed as a further development of the traditional definition of health from the World Health Organization (WHO). It is being applied in many disciplines within the health sciences. An important line of research for Klaus Hurrelmann is prevention and health promotion. Many of his research projects have focused on the social determinants of health and illness in children and adolescents. They show how the social inequality among children and adolescents also extends to health. They focus particularly on analyzing the health-related behavior of children and adolescents.