Let us suppose that at some point in the future, mankind has developed the ability to “edit” the body of the fetus, even from the earliest stages of the pregnancy, in whatever way we please. Would it be moral to operate on a fetus so that it grows up with some sort of deformity or disability? Is it ethical to purposefully cause the fetus to grow into person with no limbs, or perhaps a person who is blind?
Most people would say that it would not be. Within the context of the abortion debate, the question that must then be asked is, why is it morally acceptable to kill a fetus but not to maim it? If the personhood of the fetus has already been established in the discussion, then this can be a very convincing argument for the pro-life side. If the personhood of the fetus has not been established, however, then it can be easily answered by the pro-choice party.
Maiming the fetus would be wrong, in their view, because the fetus will eventually achieve personhood, even though it does not currently have it, and will then be hindered throughout its life by its disability. One might infer from this that it would be acceptable to maim a fetus that is scheduled for abortion. This seems rather cruel and unethical, especially if the fetus has developed to the point where it can feel pain.
But regardless of whether or not personhood has been established in the discussion, this argument shows that potential is of some value. If potential life has a right to not be maimed, then we can assume that the future of the fetus gives it some intrinsic value, whether or not it is a person while in the womb. This should at least cause people to regard abortion as something that is not to be entered into lightly or for trivial reasons.