But critics say that to get the cells, scientists must destroy fertilized human eggs. Do No Harm, a coalition of medical-ethics experts, said the new rules circumvent a 1996 law prohibiting the use of federal funding for embryo research. President Bill Clinton acknowledged the debate that continues to surround the issue. Stem cells form within four days of conception. They are parent cells to all the body's systems, later being triggered to become muscle, blood, bone, nerve, skin, organ or other tissue.
Scientists believe stem cell growth can be directed in a lab.
Eventually, the hope is to be able to grow new skin to help burn victims, replace nerve cells damaged by Parkinson's disease or repair nerve pathways to restore sensation and movement to those paralyzed by injury. Some say it may be possible to grow organs for transplant that would be genetically compatible to patients. Although research continues using adult stem cells, scientists are very interested in the embryonic form, which they believe has a less limited potential to divide. Privately funded research on embryonic cells, such as that done by the Geron Corp., is ongoing. But opening the process to federal funding will pump much more money into the process.