The issue of abortion is one of the hottest cases debated among politicians, philosophers, and all others everyday. In his essay entitled Why Abortion is Immoral, Donald Marquis adds his point of view to this much-debated topic. He acknowledges the fact that this is a difficult topic to resolve and that there are strong arguments in support of both anti-abortion, and pro-choice. Marquis defines the purpose of his essay as "developing a general argument for the claim that the overwhelming majority of deliberate abortions are seriously immoral."

Donald Marquis justifies his thesis that an overwhelming majority of deliberate abortions is seriously immoral, by placing it in the same category as the killing of an adult human being. Marquis says, "This essay sets out an argument that purports to show, as well as any arguments in ethics can show, that abortion is, except possibly in rare cases, seriously immoral, that it is in the same moral category as killing an innocent human being." His main argument is concise and to the point:

1. If it is theoretically wrong to kill me (or you, the reader), then it is theoretically wrong to abort a fetus.

2. It is theoretically wrong to kill me (or you)

3. Therefore, it is wrong to abort a fetus.

He goes on to justify, although obvious, the fact that killing me, or you the reader, is wrong, and then how he equates a fetus to be considered in the same category as an adult human.