While awaiting the birth of a new baby, North American parents typically furnish a room as the infant’s sleeping quarters. For decades, child-rearing advice from experts has encouraged the nighttime separation of baby from parent. For example, a study recommends that babies be moved into their own room by three months of age. “By six months a child who regularly sleeps in her parents’ room is likely to become dependent on this arrangement,” reports the study. Yet parent-infant ‘co-sleeping’ is the norm for approximately 90 percent of the world’s population. Cultures as diverse as the Japanese, the Guatemalan Maya, and the Inuit of Northwestern Canada practice it.