As he often does, Dr Christophersen has bridged the worlds of child development and pediatrics in his editorial on evidence-based toilet training.1 Too few pediatricians are familiar with research on child development that is germane to our role as educators and advisors of parents, and too often our advice is based on anecdotes and personal observation. The practice of pediatrics should be thoroughly grounded in developmental sciences, both biological and psychosocial, though the distinction between them is becoming less obvious with each passing year. In a profession that characterizes itself as caring for developing humans, the absence of formal education in the developmental sciences is something of an embarrassment and certainly a handicap. Pediatric training programs should design curricula to address this deficiency, and pediatricians in practice should focus some of their continuing education on this knowledge gap.