The law, I don't know. I don't think that people should smoke, but I don't think there should be a law against it. However, that to me is more of a self-destructive behavior (yeah, yeah, second-hand kills worse, I know, I know, kind-of a side point). In the case of abortion, to me, there is another person involved directly.
When it comes to an unborn child... I'm going to go with the "pro-life"ers. It is a matter of personal responsibility. If you don't want to get fat, don't eat at McDonalds 24/7, or if you do, know that you have to work out more, and eat more nutritious things as well. If you don't want a baby, don't have sex, or know that you need to take extra precautions that may or may not work and accept that. A world without consequence is a dangerous place.
As for an unborn child being alive, and having rights, that really needs to be defined. If it doesn't have rights in the case of abortion, it then shouldn't have rights in assualt and murder. i.e. killing a pregnant woman not double-homicide. i.e. if you punch a pregnant woman and the baby dies, only counts assault on the pregnant woman as the baby had no rights until it was born. Wanted or unwanted is irrelevant. I wouldn't want it that way, but I think that'd be the correct way to deny unborn children's rights consistently.
Rather, I do believe that they are alive and have rights, straight from conception. So I would rather a law against abortion. As for rape (incest or otherwise), isn't the unborn child technically innocent and a "victim" as well? Why not have an option remove the obligation and financial repsonsibility of the mother? Have the father (or state) take care of the maternity costs and adoption? Why is the knee-jerk reaction always "smash it with a rock!"? I know, that's not actually what happens, it's a turn of phrase.
However, this is something that I don't see as being within the jurisdiction of any government. There are a lot of laws that I don't agree with, there are a lot of laws that I agree with that others disagree with, so you take what you can get and advocate what you want while respecting what is established.