What are the limitations of adult/tissue stem cells?
There are currently several limitations to using adult/tissue stem cells. Adult/tissue stem cells are often present in only very limited quantities. For example, the limited numbers of blood-forming stem cells that can be isolated from umbilical cords means that these cells can only be used to treat small children, not adults. Evidence also suggests that adult/tissue stem cells do not have the same capacity to proliferate (duplicate) as embryonic stem cells do. Finally, adult/tissue stem cells do not exist in certain important tissues, as far as we know currently. These weaknesses limit the usefulness of adult/tissue stem cells.
