Homicide is the unlawful killing of a human being. There are different offences depending on the mens rea of the defendant and whether there is a special defence available to the defendant. A homicide offence cannot be charged in respect of the killing of a foetus. However, if the foetus is injured and the child is born alive but dies afterwards as a result of the injuries this can be the actus reus for murder or manslaughter. A person who is brain dead is not considered a reasonable creature in being. The phrase abnormality of mind in the Homicide Act 1957 was wide enough to cover the perception of physical acts and matters, the ability to form a rational judgment as to whether an act is right or wrong and an ability to exercise willpower to control physical acts in accordance with that rational judgment.