"The first application of the principle of double effect, and one of the most consistently important issues in medical ethics, is that of abortion. Gradually, Roman Catholic medical ethicists arrived at a consensus as to the exact application of double-effect physicalist criteria, which enabled them to make clear and precise judgments in each kind of abortion situation. These distinctions and judgments are now questioned in part by some proportionalist/revisionist Catholic scholars, but they remain the basis for official Catholic teaching (National Conference of Catholic Bishops 1995, dir. 45-50). Direct abortions are those in which the act-in-itself is the removal of the fetus “directly” from the body of the woman, or the “direct” killing of the fetus by any other means while still within the mother’s body. These acts are never permitted and are considered gravely immoral, identical to murder. Indirect abortions are, however, permitted according to the principle of double effect. Here the act-in-itself is specified as an operation or other procedure whose directly intended effect is the preservation or restoration of the mother’s health. The foreseen but unintended death of the fetus is “indirect”. The two classic cases are the removal of a pregnant cancerous uterus and the removal of a fallopian tube in the case of ectopic pregnancy. Other cases are the use of certain medications or operations where there is some danger that the fetus may die as a result, but where the procedure is directed at some other effect. Thus, for example, an appendectomy may be performed on a pregnant woman, even though some (perhaps even great) danger exists of a consequent abortion (miscarriage)."