Yes, we have turned unborn children into kidneys and the like.
If that's how you feel about it then you've completely misunderstood the analogy. The analogy speaks to how we actually view human life versus a blastocyst/zygote/fetus. And it demonstrates quite nicely that anti-abortionist actually want to confer special rights upon blastocysts/zygotes/fetuses that we don't even extend to actual birthed, living breathing human beings.
The blastocyst/zygote/fetus is not the kidney in the analogy. The blastocyst/zygote/fetus is the person who needs your kidney in order to survive. Maybe that helps you understand it better?
And not just early stage, but late stage for the convenience of a woman who decides at the last moment .....
Ah, there's that word again - "convenience." Used to dismiss, demean and patronize women about choices they're making for their own lives. I really wish we could trash that bit of misogyny already.
As pointed out several times now, that almost never happens. The vast majority of "late term abortions" are done when something has gone horribly wrong in the pregnancy and it's a necessary procedure to save the woman's life.
I see no difference between slavery and abortion.
Maybe that is because, and I'm sorry to have to point this out, you don't seem to understand how analogies work.
The slavery analogy can work if we use it correctly though. As in, taking away someone's bodily autonomy makes them nothing more than a slave who can't make their own decisions about their own lives and their own bodies. Where someone else makes those decisions for them. Ever seen or read
The Handmaid's Tale?
And I have no doubt that one day we will kill infants too.
The ancient Spartans used to do that. My nana used to work in a Catholic Church that did that.
We don't do that anymore.