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.
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.