Sudden infant death syndrome (SIDS) is a very rare incident; it occurs in less than ½ per mill of all infants. James J. McKenna (University of Notre Dame) has discovered that co-sleeping mothers and infants not only synchronize their sleep-wake-rhythm, but their breathing, too; he therefore reasons that co-sleeping lowers the SIDS risk.[60] Nonetheless, studies that investigate SIDS directly have shown that permanent bed sharing rather raises the SIDS risk than lowering it.[61] The U.S. Consumer Product Safety Commission also warns against co-sleeping.[62] Attachment Parenting International issued a response which stated that the data referenced in the Consumer Product Safety Commission statement were unreliable, and that co-sponsors of the campaign had created a conflict of interest.[63] The American Academy of Pediatrics' policy on SIDS prevention opposes bed-sharing with infants, although room-sharing is encouraged.[64]