What are the disadvantages of using adult stem cells?

It is difficult to isolate and extract adult stem cells, and their reproductive capacity is somewhat more limited than that of embryonic stem cells. Additionally, they are much harder to grow and reproduce on a medium outside the body.

An extension of this problem is that obtaining a pure, uniform sample of adult stem cells is highly challenging. This presents a big problem for scientists who rely on constants for experiments, which must be completed and repeated before conclusions may be drawn. It is much more difficult to procure identical adult stem cells, which may severely limit their usefulness to scientists.

Finally, only a few of the 220 types of cells have been produced using adult stem cells. Though evidence of greater plasticity has recently been put forth, the problems mentioned above may prevent the wide application currently available with embryonic stem cells.

The future of stem cell research

The debate about stem cell research is not limited to the United States. Several European countries and China have banned embryonic stem cell research, but other developed nations such as Britain, Israel, and Japan have passed legislation allowing it. Observers on both sides of the argument generally agree that the issue is not likely to fade away, and that future advancements in the areas of stem cell and cloning research will inevitably raise as many questions as answers in years to come.