A third person claiming one of your organs--- say your liver ---  is not remotely comparable to a fetus, whose entire body and life reside within the mother, claiming nothing more than its own right to live.  And the mother who denies the baby's right by killing it does something vastly different from denying the stranger her liver.  Indeed, there is a closer comparison between you actively killing the stranger with a gunshot and you killing a fetus --- in both cases, you have killed a human being.  The one thing that saves you from a murder charge in the latter case is your own ignorance.
*****
"People own their bodies. If you do not believe that women own theirs, then you do not believe women are people, human beings with rights, who can move and feel pain just like you claim the unborn can."  

That people own their own bodies does not mean that they have a right to kill other people, who also own their own bodies.

*******
cont'd