The biomedical research community has made great strides toward jettisoning the notion that “children are little adults.” It is now well recognized that children’s unique patterns of health and disease, growth and development, and dependency on adults for managing their health provide strong justification for the field of pediatric research. The types, manifestations, and frequency of various diseases as well as the adverse event profile for medical treatments can differ between adults and children, and sadly conditions such as hypertension and metabolic syndrome once considered adult-onset have infiltrated childhood. Maturation of children’s physiology influences the qualitative and quantitative effects of medical products, which calls into question the use of “hand-me-down” results from medical product studies done among adults. Particularly for infants and young children we rely on parents and caregivers to implement treatments and to provide their observations on treatment effects.