In fact when you combine stem cell technology with the technology known as tissue engineering you can actually grow up entire organs, so as you suggest that sometime in the future you get in an auto accident and lose your kidney, we'd simply take a few skin cells and grow you up a new kidney. In fact this has already been done.
Robert LanzaPhysics tells us observations can't be predicted absolutely. Rather, there's a range of possible observations each with a different probability.
Robert LanzaFor example, if the big bang had been one-part-in-a billion more powerful, it would have rushed out too fast for the galaxies to form and for life to begin.
Robert Lanza