The philosophical aspects of the abortion debate are logical arguments that can be made either in support of or in opposition to abortion. The philosophical arguments in the abortion debate are deontological or rights-based. The view that all or almost all abortion should be illegal generally rests on the claims that (1) the existence and moral right to life of human beings (human organisms) begins at or near conception-fertilization; that (2) induced abortion is the deliberate and unjust killing of the embryo in violation of its right to life; and that (3) the law should prohibit unjust violations of the right to life. The view that abortion should in most or all circumstances be legal generally rests on the claims that (1) women have a right to control what happens in and to their own bodies; that (2) abortion is a just exercise of this right; and that (3) the law should not criminalize just exercises of the right to control one's own body and its life-support functions.
Although both sides are likely to see the rights-based considerations as paramount, some popular arguments appeal to consequentialist or utilitarian considerations. For example, anti-abortion groups sometimes cite alleged medical and psychological risks of abortion, such as the existence of post-abortion syndrome or the abortion–breast cancer hypothesis. On the other side, abortion-rights groups say that criminalizing abortion will lead to the deaths of many women through "back-alley abortions", that unwanted children have a negative social impact, or conversely cite the legalized abortion and crime effect, and that reproductive rights are necessary to achieve the full and equal participation of women in society and the workforce. Consequentialist arguments on both sides tend to be vigorously disputed, although they are not widely discussed in the philosophical literature.