It is questionable whether the casual blurring and switching of subjects between stem cell research, therapeutic cloning, and reproductive cloning technologies is intentional. Some have suggested that adult stem cells may be sufficient to pursue all treatments for human disease. Studies done with adult stem cells do, in fact, show that adult stem cells have the capacity to form essentially any tissue. Unfortunately, more research dollars and effort are put into embryonic stem cell research than adult stem cell research because they have been held up as the panacea for disease and a fountain of youth. This occurs despite the scientific and ethical advantages of using adult stem cells.
Current evidence suggests that adult stem cells have markedly restricted differentiation potential.
Therefore, for disorders that prove not to be treatable with adult stem cells, impeding human pluripotent stem cell research risks unnecessary delay for millions of patients who may die or endure needless suffering while the effectiveness of adult stem cells is evaluated. It may be true that adult stem cells have some restricted differentiation potential. This disadvantage can be overcome with appropriate research dollars and effort. The results of Clarke et al. Moreover, there are distinct advantages to using adult stem cells over embryonic stem cells.