I have not before entered the waters on the abortion debate, but it seems to me to be a moral issue; either it is permissible to abort a baby or it is not. I contend that it is impermissible to abort a baby at any stage, given a few basic assumptions. I will briefly sketch an argument for this.
1. If something is a person, it has intrinsic moral value.
2. Whatever has intrinsic moral value ought not to be killed unless there is a morally-sufficient reason.
3. Human beings are persons.
4. Therefore, human beings have intrinsic moral value.
5. Therefore, human beings ought not to be killed unless there is a morally-sufficient reason.
6. It is not morally permissible to end the life of an innocent human being to save one’s own.
7. Unborn babies are innocent human beings.
8. Therefore, unborn babies are persons.
9. Therefore, unborn babies have intrinsic moral value.
10. Therefore, unborn babies ought not to be killed unless there is a morally-sufficient reason.
11. Therefore, it is not morally permissible to end the life of an unborn baby to save one’s own.
A few brief comments are needed. First, I ask that one lay aside emotion and rhetoric and look it from a stance of pure logic and reason. Second, please notice that, so long as the premises are true, a woman’s right to choose or psychological reasons to be against abortion or sexism are simply irrelevant. Third, statements 4, 5, and 8-11 are conclusions of deductively-valid arguments and cannot be denied. Premise 1 could be denied in the case that one declares there are no objective moral values. However, most people who take this road in hopes of preserving abortion do not realize that I can just say, “Well then it’s not morally impermissible for me to restrict a woman’s right to choose, is it?” In any case, most people will be forced to agree there are moral truths. Someone could affirm objective moral values but deny that persons have intrinsic moral worth; this would be something I could not even begin to grasp.
Premise 2 seems reasonable enough on any moral theory; one could affirm it even if there are never any morally-sufficient reasons for killing anything of intrinsic moral worth. Most will agree with premise 3. Some might object that not all human beings are truly persons, but I struggle with saying certain human beings are non-persons. In any case, some non-arbitrary definition ought to be applied that does not marginalize the mentally disabled, or someone who was in a car accident, etc.
It is also difficult to argue with (6). When we say “innocent,” we are using it in a univocal sense in this argument, and it means “morally innocent with respect to a particular situation.” Suppose two men were struggling in the ocean with only one life preserver. We would rightly be appalled at one man if he were to drown the other just for the opportunity to save his own life. Now suppose a crazed terrorist has kidnapped someone to launch them from a cannonball directly into you. The speed and impact will kill you both. Is it morally permissible then just to kill the other innocent party? Perhaps someone would do it, in desperation, but the right answer is no. Just because it’s one or both of you who will die doesn’t make it right to kill an innocent party. Finally, (7) is almost true by definition, at least biologically and morally. For an unborn baby, or fetus, is not biologically different from a human. Moreover, the unborn baby is innocent in the relevant sense. But then we see abortion is not morally permissible.
So we have seen it is not morally permissible to abort an unborn baby. Notice we did not appeal to women’s rights (or lack thereof), death of the mother, or in the cases of rape, incest, or other terrible things. We did not minimize any of these things. But it is incontrovertible that these things are not relevant to the argument above. The cost of denying any of these premises is too high, epistemically, compared to rejecting abortion. But if none of the premises are denied, then all of the conclusions follow.
 How curious would it be to say two humans can reproduce something non-human, biologically, that somehow later turns into a human! Moreover, it is just genetically human.