A week-old baby is not a rational and self-aware being, and there are many nonhuman animals whose rationality, self-awareness, capacity to feel and so on, exceed that of a human baby a week or a month old. If, for the reasons I have given, the fetus does not have the same claim to life as a person, it appears that the newborn baby does not either.
Peter Singer, Practical Ethics
ethics, utilitarianism