mainly it's all about the person given the option of an easy out for what is deemed "illegal" for most certain irresponsible actions of their own doing. of course there are circumstances that is not the case but for the most part it is. however, the dilemma is that the life of another human being
The first thing I want to point out is that characterizing the fetus as a human being is a bit disingenuous. The question of "When does life begin" is still largely driven by belief, and science hasn't provided a clear cut answer yet.
And it is no secret that most abortions are due to unwanted pregnancies. Considering that there aren't contraceptives that are 100% effective, it's quite rich to talk about lack of responsibility; furthermore, pregnancy is rough on women, and they should have the freedom to not want to go through that.
the dilemma is that the life of another human being is involved in this matter. that is why there were some debate of de-humanizing or trying to change the definition of what is a living person. some even go to the point of categorizing a fetus as non-living or not human just to get what they went.
This take ignores the mechanics of pregnancy and the fact that the fetus behaves pretty much like a parasite until much later in the pregnancy: upon conception, it has to be attached to the uterus or it dies. Is it death? Is it murder? Is it manslaughter?
If it gets attached to the fallopian tubes, it pretty much kills the mother if it isn't aborted. Who's responsible for the mother's death, since she doesn't get to decide where the fetus gets attached? Are we putting the fetus on trial? We can't.
This is a caterpillar. We know what its final form will be (a butterfly), but it is not a butterfly right now. It has no wings, and it can't fly. Are we still supposed to call it a butterfly?
From a legal standpoint, pro-life people want it both ways: they want to claim that fetuses are full blown humans, but they wont allow them to be claimed on our taxes; they won't allow a pregnant woman to ride in the carpool lane. They have no citizenship, no name, no duties.
None of this makes sense unless it is understood as one group of people has declared that their understanding of pregnancy and all the issues surrounding it is the only one that matters, and that everyone else will live according to that particular view.