Context Stem cell therapy is rapidly developing and has generated excitement and promise
as well as confusion and at times contradictory results in the lay and scientific literature.
Many types of stem cells show great promise, but clinical application has lagged due to
ethical concerns or difficulties in harvesting or safely and efficiently expanding sufficient
quantities. In contrast, clinical indications for blood-derived (from peripheral or umbilical cord
blood) and bone marrow–derived stem cells, which can be easily and safely harvested, are …