Some doctors closely involved with children suffering from severe spina bifida believe that the lives of those worst affected are so miserable that it is wrong to resort to surgery to keep them alive. Published descriptions of the lives of these children support the judgment that they will have lives filled with pain and discomfort. When the life of an infant will be so miserable it would not be worth living, and there are no 'extrinsic' reasons - such as the feelings of the parents - for keeping the infant alive, it is better that the child should be helped to die without further suffering. A more difficult problem arises when we consider disabilities that make the child's prospects significantly less promising than those of a normal child, yet not so bleak that the child's life would not be worth living. A haemophiliac, for instance, lacks the element in blood that makes it clot, and thus risks prolonged bleeding, especially internally, from the slightest injury.*If allowed to continue, this bleeding leads to permanent crippling and, eventually, death. The bleeding is very painful, but most haemophiliacs find life definitely worth living. Now, suppose that a newborn baby is diagnosed as a haemophiliac. The parents, daunted by the prospect of raising him or her with this condition, are not anxious for the baby to live. Could euthanasia be defended here? Our first reaction may well be a firm 'no'. The infant exists. His or her life can be expected to contain a positive balance of happiness over misery.*To kill him would deprive him or her of this balance of happiness. But the utilitarian must ask whether the death of the haemophiliac infant would lead to the creation of another being who would not otherwise have existed. If the child is killed, will his parents have another baby who they would not have had if the haemophiliac child had lived? And is a second child likely to have a better life than the first? Suppose a woman planning to have two children has one normal child, then a haemophiliac child. The burden of caring for the second child may prevent her from having a third: but if the disabled child were to die, she would have another. When the death of a disabled infant will lead to the birth of another child with better prospects of a happy life, the total happiness will be greater. The loss of a happy life to the second infant is outweighed by the gain of a happier life for the third. So, if killing the haemophiliac infant has no adverse effect on others, it would, according to this view, be right to kill him. This view treats infants as replaceable. Many will think that this argument cannot be applied to human infants. The direct killing of even the most hopelessly disabled infant is still officially regarded as murder: how, then, could the killing of infants with far less serious problems, such as haemophilia, be accepted? And yet, there are disabled members of our species whom we now deal with exactly as the argument suggests we should. There is only one difference between these cases and those that we have been discussing, and that is one of timing. Prenatal diagnosis is now routine, and pregnant women are offered, and usually accept, abortions in order to avoid given birth to children with haemophilia. The same can be said about other conditions that can be detected before birth, such as Down's syndrome. A disabled foetus is often aborted. I can't see how one could defend the view that foetuses may be 'replaced', but newborn infants may not be. The fact that a being is a human being is not relevant: it is, rather, such characteristics as rationality, autonomy, and self- consciousness that make a difference. Self-consciousness is not to be found in either the foetus or the newborn infant. Neither is an individual capable of regarding itself as a distinct entity with a life of its own to lead. Killing them, therefore, cannot be equated with killing normal human beings. The potential of a foetus to become a rational, self-conscious being cannot count against killing it at a stage when it lacks these characteristics - unless we are also prepared to count the value of rational self-conscious life as an argument against contraception and celibacy. This position does not imply that it would be better if all babies born with severe disabilities died; only that the parents of such infants should be able to decide whether they do or not.*Nor does this imply lack of respect for people with disabilities who are now living their own lives in accordance with their own wishes. Even those who reject abortion and the idea that the foetus is replaceable are likely to regard possible people as replaceable. Suppose a woman is planning to become pregnant. She is told by her doctor that, if she goes ahead immediately, her child will have haemophilia, but if she waits three months, her child will be normal. If we agree with her decision to wait, it can only be because we are comparing the two possible lives and judging one to have better prospects than the other. Of course, at this stage, no life has begun; but the question is: when does a life, in the morally significant sense, really begin? Regarding newborn infants as replaceable, as we regard foetuses, would have considerable advantages over prenatal diagnosis followed by abortion. Prenatal diagnosis still cannot detect all major disabilities. Some, in fact, are not present before birth, they may be the result of premature birth or of something going wrong during labour. At present, parents can choose to keep or destroy their disabled offspring only if the disability is detected during pregnancy. But, if disabled newborns were not regarded as having a right to life until, say, a week or a month after birth, it would allow parents, in consultation with doctors, to make a more informed decision. Obviously, to go through pregnancy and labour, only to give birth to a child who one decides should not live, would be heartbreaking. For this reason, many women would prefer prenatal diagnosis and abortion to the possibility of infanticide, but if the latter is not morally worse than the former, it is a choice that the woman herself should be allowed to make. So the issue of ending life for disabled newborns is not without complications. But the main point is clear: killing a disabled infant is not morally equivalent to killing a person. Very often it is not wrong at all.