Wanted: Stem Cell Super Donors

Our bodies' cells didn't evolve to flourish in a petri dish. Even fast-growing skin cells stop dividing and turn thin and ragged after a few weeks outside the body. This natural obstacle limited the therapeutic potential of lab-grown cells - if you can't grow the cells, you can't use them to heal damaged tissue. Then, a decade ago, Nobel Prize winner Shinya Yamanaka identified a cocktail of genes that, when added to mouse skin cells, transformed them into a new kind of cell that grew happ