Based on what? Religion?

It has nothing to do with religion and everything to do with the fact that they're human beings. This is the only definition that isn't completely arbitrary and ensures the rights and liberties of every human being without justifying killing anyone who shouldn't be killed.

So, to be clear, once a person has already been deprived of their freedom and liberty by one person, they should continue to be deprived of their liberty?

Being forced to carry a pregnancy is a lesser violation of someone's rights than killing someone who could not possibly be held responsible for what happened. Or do you think that murder is a human right?

where would you stand on forced organ donation? That is, you're a tissue match to me, and I need a kidney. Would you be okay with being legally obligated to undergo surgery and give a kidney to me so I can live?

So let's seriously consider the implications of this Looney Tunes Medical Malpractice Extravaganza world you've just invented without any actual basis in reality. First of all, dialysis and consensual organ donation exist. These facts alone make this whole question nonsense, but you haven't insinuated you want to kill me, so I'll answer your question despite the fact it's absurd from the get-go.

Second, the vast majority of these "forced" transplants would happen because of consensual activity that somehow is designed to lead to this outcome. On top of that, this activity would also require you to spontaneously develop kidney failure without being involved. Again, for the sake of argument, let's pretend that isn't just outright impossible. That hilarious fact aside, if you cannot handle the possibly of having children, you should not be doing things that are designed to produce children. Similarly, if you cannot handle needing to donate a kidney, you should not do things designed to lead to a kidney donation. If this were the case, then this would be happening for all of human history, and the human body would have an actual mechanism for doing this and the question would actually have a meaningful answer.

And before you go off about how car drivers don't consent to accidents, just know that moving around the world, going to your job, seeing your friends and family, that kind of thing, is an actual requirement to live unless you're completely homebound. You aren't going to drop dead or starve to death because you didn't get enough quickies in with someone else.

Third, there is no way for a fetus to survive a pregnancy other than to carry on through that pregnancy. The fact that other options exist to help you survive your predicament exist means you don't have the right to steal people's organs.

Fourth, you have agency in this situation; the baby doesn't. You may need a kidney transplant because of a completely preventable illness; the baby doesn't have that luxury. Babies will only ever be born once, but if you had the legal right to steal a kidney every time you got sick, you could just keep doing whatever it is screwed your last kidney up.

Fifth, if this was actually permissible, medical ethics as a whole would be completely up-ended. It would mean that people who chose to get themselves into bad situations had the right to rob people of vital functions to get themselves out of them. Again, this does not apply to babies.

I could go on, but I think you get the idea. Using the logic of the real world where abortions kill hundreds of thousands of people every year, no, neither that nor the blood stealing example would be permissible. But because neither of these things is actually analogous to pregnancy, they're moot points.

Now you riddle me this: how long after conception is it acceptable to kill the fetus without any justification? Why does it end there, and not before or after? Also, why is it okay to kill someone for being the victim of a crime? After all, the conceived child is as much a victim here as the woman is. If it's not okay to kill someone for being the victim of a crime, then it's not okay to get an abortion because of rape.