The murder of young children, either individually or en masse, is usually a result of social attitudes. Infanticide has historically been associated with the birth of a deformed or abnormal child, of twins, or of a female child. The major contributing factor is generally poverty, although illegitimacy also plays a large role, especially in more contemporary societies. Infanticide also occurs during movements of people – warrior societies in the past, and refugee movements in recent times – and as a means of evading governmental policies such as China's "one child per family". Instead of outright infanticide, the child may be abandoned (though few are found alive), while other cases take the form of ritual sacrifices.
Infanticide has been a common practice since earliest prehistoric times among pagan, primitive tribes throughout the world. An example of the latter is the Jagas tribe of west Africa which killed all its own children, maintaining the population by adopting the children of its victims. Infanticide was strongly recommended by both Plato and Aristotle as a means of ensuing the stability of the population of Athens. In traditional Japanese culture, the term used was "thinning the family", whereby daughters were not killed at birth but were allowed to grow to an age when their strength or intelligence became apparent (2 to 4 years). The weaker were then drowned or decapitated. Infanticide was extensively practised in ancient China, especially in times of famine. It was a common practice in Rome where the father had the right to dispose of unwanted children by throwing them in the Tiber.
Examples of infanticide can be found in all societies, both past and present, ranging from isolated individual instances to general policy. Much attention has been focused on the practice in modern China where the number of infanticides (generally females) may exceed 10,000 per year, according to the USA National Academy of Sciences.
All human beings derive their essential value not from society, or from their parents but from God who gave them their life an to who they are infinitely precious. Society is judged by the extent to which it cares or fails to care for its weaker members. The parents may feel profoundly sorry for their handicapped child; and not only sorry for themselves, as is sometimes the case; but the decision to kill the child even for what they deem to be his or her 'own good' is one which they are not morally competent to make. The right to life is the infant's, and it is their own subjective feelings by which they judge that it would be better for the child to die. It is never morally permissible deliberately and directly to kill any innocent person. Morally there is no difference between infanticide and murder.
The painless killing of newborn children who have gross physical or mental handicap is in the interest of their own family and of society as a whole because they would otherwise become an increasing social and economic burden to the community. It is in the infants' own interest and is an act of compassion as they cannot expect to enjoy the pleasures and opportunities available to normal children and adults. It is kinder to spare them the frustrations and hardships they must otherwise inevitably experience. Infanticide should be regarded as a less heinous offence than the murder of a grown child or adult, because an infant cannot experience fear or terror or even pain in a comparable degree, nor does its removal impose any significant hardship or loss on the family circle.
In India, it is argued that an unwanted baby is better being killed than living out its life with strangers as a result of adoption.
In some societies dealing with harsh environments, infanticide is an ecologically adaptation to reduce population to a size sustainable by the environment; maintain balance sex ratios among adults as young male hunters have high mortality rates; and helps preserve more older persons who are more productive than infants, and their accumulated knowledge increases information storage and retrieval for the group.