Since stem cells do not yet have the genetic coding which tells them what kind of cell to become (systemic, nerve, vascular, etc.), we have the ability to give them that genetic information so that they become whatever kind of cell we want. This would be especially helpful in growing and replacing kinds of cells that do not undergo mitosis (or reproduce to form new cells), like nerve and muscle cells. This means that, theoretically, we could regrow new heart tissue for heart attack patients. Unfortunatly, stem cell research isn't yet legal in the U.S.