Many people object to the use of embryonic stem cells, contending that the research requires the destruction of potential life, because the cells must be extracted from human embryos.
The stem cells being used in the recently approved Geron trial were obtained from one of the Bush administration's approved stem cell lines. And no federal funds were used in the development of this treatment.
Since the restrictions on embryonic stem cell research took effect, many research institutions have redirected their focus to other types of stem cells. Prockop's institution, for instance, deals only with adult stem cells.
Adult stem cells can give rise to all the specialized types of cells found in tissue from which they originated, such as skin. But, scientists don't agree on whether adult stem cells may yield cell types other than those of the tissue from which they originate, according to the National Institutes of Health.
To learn more about stem cells, visit the U.S. National Institutes of Health.
SOURCES: March 6, 2009, statement, Peter T. Wilderotter, president and CEO, Christopher And Dana Reeve Foundation, Short Hills, N.J.; March 6, 2009, statement, Philip Pizzo, M.D., dean, Stanford School of Medicine, California; Darwin Prockop, M.D., Ph.D., director, Texas A&M Health Science Center College of Medicine Institute for Regenerative Medicine at Scott & White Hospital, Temple, Texas; The New York Times
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