> I think people want to make it about that, and that's fine.

Well, from a moral perspective, it is about that. I'm not sure which of those two positions you take (not a person / mother's rights supersede children's rights), but if you're going to be honest you've got to figure out which it is and why.

And for the vast majority of people who vote pro-life (at least, all the ones that I know), that's what it's about too. And I note that you haven't really challenged the core logic I've put forward there, but rather on some of the sticky implications.

> Oh, and the person you are donating to has Alzheimer's and you have to take care of them until either one of you die. ...The woman is forced to... take care of it for the rest of each others lives.

And, here's again where there's a basic ignorance that a five-minute conversation with someone who's pro-life would clear up. Nobody who's pro-life would say that women should be forced to raise the children; they can be put up for adoption.

> But should we force people to donate their livers, kidneys, bone marrow because someone will die otherwise?

There's a difference between causing someone to die by action, and allowing someone to die by inaction. Pushing someone into a raging river is different than failing to dive in to rescue them.

> Forced birth is kinda/sorta/almost the same thing. The woman is forced to donate aspects of themselves that will affect them forever (more than just 'organs' in some ways), they may not even live through the event...

This is your strongest point. I mean, yeah, birth is crazy. And it would totally suck to go through it if it wasn't something you'd chosen to do. But it's not like the child was able to choose this either. It's a terrible situation for both people.

> Long ago, I dated a woman who had broken her hip in such a way she could not have a child without losing the ability to walk for the rest of her life.

So first of all, this sort of situation is quite uncommon; and while there are zealots who would take a hard line, lots of people would be willing to compromise in this sort of a case. Secondly, there are lots of people worldwide who are OK with abortion in the first trimester, but not the second and third. I think there are reasonable justifications for this.

But thinking about it from a moral perspective, let's try this scenario.

You're taking a tour of some tall factory with a bunch of people you don't know. While you're on a catwalk 4 stories up, something catastrophic happens, and at the end of it you're holding for dear life to a railing, and a stranger is dangling over the factory floor, holding for dear life to your legs.

You're not afraid of falling yourself; your arms are wrapped firmly around the railing, which you're pretty sure isn't going anywhere. But you have some sort of a degenerative joint disorder in your hips. You can already feel the tendons stretching from the stranger dangling below you; you're pretty sure that by the time help arrives to pull him up that enough damage will be done that you'll never walk again. You're also pretty sure that if you kick him hard enough right now, he'll let go and fall to his death, leaving your legs intact.

Is it moral for you to kill the stranger to save your legs? Should it be legal to kill the stranger to save your legs?