In Reply.— Guntheroth and Spiers,1 displeased with our commentary in Pediatrics,2 have raised many issues. However, the key question is whether the scientific data incriminating the prone position as a contributor to SIDS warrant a recommendation to change sleeping position at this time. Based on our critical review of the literature, we conclude that this recommendation was premature and unwarranted. Accepting the current definition of SIDS as the sudden death of an infant that remains unexplained even after a thorough postmortem examination, death scene investigation, and review of the clinical history, one can decide which of the 15 published studies in which a statistical association is described between prone sleeping and SIDS is acceptable.