Although it is commonplace to refer to the killing of any child--newborn or older--by either parent as infanticide, current legal definitions of infanticide and filicide are well defined and are quite country-specific. According to Black's Law Dictionary as used in the United States' legal system, for example, infanticide is: "1. The act of killing a newborn child, esp. by the parents or with their consent. In archaic usage, the word referred also to the killing of an unborn child.--also termed child destruction; neonaticide. 2. The practice of killing newborn children. 3. One who kills a newborn child" (781). Other U.S. legal experts have defined infanticide as the term generally used when describing the killing of infants or children. Infanticide itself has also been further narrowed by distinguishing between the killing of an infant within twenty-four hours of birth (neonaticide) and the killing of an infant or child older than twenty-four hours (filicide) (Dvorak 2). The Canadian legal system uses a much more narrow--and yet more widespread--definition: "A female person commits infanticide when by a willful act or omission she causes the death of her newly-born child, if at the time of the act or omission she is not fully recovered from the effects of giving birth to the child and by reason thereof or of the effect of lactation consequent on the birth of the child her mind is then disturbed" (Consolidated Statutes of Canada. Criminal Code, Part VIII. 233). The history of such legal definitions is particularly revealing in Great Britain, the basis of the Canadian law. The British Infanticide Act of 1922 reduced the crime of infanticide from murder to manslaughter on the basis of insanity. This change was premised upon the belief that a woman who commits infanticide may do so because "the balance of her mind [is] disturbed by reason of her not having fully recovered from the effect of giving birth to the child" (Meyer, Oberman et al 11, 171, 183; see also Pearson 80). This statute was revised in 1938 and extended the age of victims from "newly born" to "under the age of 12 months" and cited specifically the "effect of lactation" on a woman's mind (Pearson 80; Morris and Wilczynski 204). The British Infanticide Act has been replicated in slightly varying forms in at least twenty-two nations around the world. Dvorak notes that the majority of neonaticide/infanticide statutes in these countries make the crime a lesser offense than homicide and that although countries may define infanticide differently, the most common elements include a mother who kills her infant after the child has been born because the mother had not fully recovered from the effects of giving birth (Dvorak 5). These statutes link infanticide, in effect, to mental illness, thereby medicalizing the crime and limiting the defendant's culpability to manslaughter rather than murder (Meyer, Oberman et al. 11, 13, 183).