Stem Cells Used to Create a Beating Rat Heart
Another excellent milestone on the road to creating viable organs, coupling this with the ability to revert skin cells to stem cells and you just might have the biggest two medical advances that I can think of.
When you can dramatically extend life expectancy at high cost, and have the rich living three or four times longer than the poor, you also get some very interesting ethical and moral issues, not to mention social issues.
It happens already between countries (take the U.S.As 78.2 year life expectancy and compare it to Swazilands 39.6, for example), but if it starts happening within countries and along such strict castes (rich people get new organs, poor people don’t), I wonder what implications that might have.