DARYN KAGAN, CNN ANCHOR: At this hour, the White House wades into the emotionally charged question of when does life begin. The Clinton administration is releasing guidelines that will allow research on fertilized human embryos. Antiabortion groups say that violates sanctity of human life. While researchers say it offers the chance of a lifetime for people with serious health problems. Some medical perspective now from CNN's Elizabeth Cohen.</s>ELIZABETH COHEN, CNN CORRESPONDENT (voice-over): They keep stem cells under lock and key. Stem cells are so valuable because one day doctors think they will be used to treat all sorts of ailments, everything from heart disease to skin burns to Parkinson's Disease.</s>DR. JOSEPH ITSKOVITZ, RAMBAM MEDICAL CENTER: We can devote new technologies that are going to revolutionize medicine.</s>COHEN: What exactly are stem cells? They are blank cells that potentially can be turned into virtually any tissue in the human body, basically creating a supply of spare body tissues.</s>UNIDENTIFIED MALE: So imagine you can grow up million of cells in a dish, and then giving it a signal of some sort, you can then convert those cells into a million neurons of some kind, or a million cardiac muscle cells.</s>COHEN: And what would doctors do with a supply of cardiac muscle cells? When someone has a heart attack these cells are damaged. A dose of new cells made in the lab could heal the damage. So when will all this happen?</s>UNIDENTIFIED MALE: I think, with certain cell types, we could certainly consider a 5-7 year period as being within reach.</s>COHEN: Only three universities have managed to manufacturer stem cells in the lab. Two do so they had to start with a human embryo or fetus. Doctor John Dearhard (ph) used aborted fetuses. Dr. Joseph Itskovitz in Israel used fertilized eggs that were in a lab and no longer needed by couples undergoing fertility treatments.</s>KAGAN: And that report from CNN medical correspondent Elizabeth Cohen.
Stem Cells Offer Doctors Supply of Spare Body Tissues