Moral issues of embryonic stem cells may be bypassed by harvesting adult ones

• In the emerging field of stem cell research, much of the promise -- and most of the controversy -- involves the breathtaking notion that replacement parts for our bodies one day may be grown from multipurpose cells derived from human embryos.
• But scientists also are learning that embedded in our skin, flowing in our blood and stored in the deep reaches of our bones and brains are less versatile breeds of "adult" stem cells that may yet be coaxed into producing the same sort of medical advances without disturbing the ethical waters.
• Because adult stem cells can be harvested without destroying a human embryo, they are the technology of choice among those, like President Bush, who have moral objections to research involving embryonic stem cells.
• At a White House gathering last month, the president reaffirmed his opposition to such research but said his administration strongly supported the use of "alternative sources" of stem cells such as bone marrow and umbilical cord blood.
• Adult stem cells do not have the ability to turn into virtually any organ or tissue in the human body -- that is a trick reserved for their embryonic counterparts.
• Adult stem cell therapy is already being tested on patients.
• In fact, bone marrow transplantation -- pioneered three decades ago -- is adult stem cell therapy by another name.
• Bone marrow transplants have provided the "proof of principle" that stem cells have therapeutic potential, said Dr. Arnold Kriegstein, director of the Program in Stem Cell and Developmental Biology at UCSF.
• At the Texas Heart Institute in Houston, controversial clinical trials are already under way, using adult stem cells in older patients with failing hearts whose only alternative is a hard-to-come-by transplant.