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.

The patients who received the human embryonic stem cell transplants say their lives have been transformed by the experimental procedure. He currently resides in Clinton Massachusetts. Publications
Lanza has authored and co-edited books on topics involving tissue engineering cloning stem cells and world health.

Robert Paul Lanza (born 11 February 1956) is an American Doctor of Medicine scientist Chief Scientific Officer of Advanced Cell Technology (ACT) and Adjunct Professor at the Institute for Regenerative Medicine Wake Forest University School of Medicine.