Infanticide
The deliberate killing of newborn infants has long been practiced in human societies. It seems to have been common in the ancient cultures of Greece, Rome, and China, and it was practiced in Europe until the 19th century. In Europe, infanticide included the practice of “overlaying” (smothering) an infant sharing a bed with its parents and the abandonment of unwanted infants to the custody of foundling hospitals, in which one-third to four-fifths of incumbents failed to survive.
In many societies practicing infanticide, infants were not deemed to be fully human until they underwent a rite of initiation that took place from a few days to several years after birth, and therefore killing before such initiation was socially acceptable. The purposes of infanticide were various: child spacing or fertility control in the absence of effective contraception; elimination of illegitimate, deformed, orphaned, or twin children; or sex preferences.
With the development and spread of the means of effective fertility regulation, infanticide has come to be strongly disapproved in most societies, though it continues to be practiced in some isolated traditional cultures.