The idea that a developing fetus is part of the woman’s body is so biologically ignorant that I would call it medieval, except that would be to insult the medievals! The fetus is not like an appendix or a gall bladder. From the moment of its conception and implantation in the wall of the mother’s uterus, the fetus is never a part of her body, but is a biologically distinct and complete living being which is, in effect, “hooked up” to the mother as a life-support system. To say a fetus is part of a woman’s body is like saying that a person on life support is part of the iron lung or the intravenous equipment. Having an abortion is not like having an appendectomy. It is killing a separate human being, and to try to justify that on the grounds that a woman can do what she wants with her own body is just politically correct ignorance.
William Lane Craig, Hard Questions, Real Answers, Wheaton, 2003, pp. 118-119