Which type of stem cell is best?
That is unknown. Some researchers believe embryonic stem cells are best because they are the most versatile. Also, embryonic stem cells can grow vigorously, forming colonies that will expand virtually forever. But research has shown that adult stem cells also are capable of forming many different types of cells. For instance, some mouse experiments have shown that neural stem cells from the brain can be coaxed into growing muscle, liver and heart cells. Adult stem cells, though, are more difficult to grow and do not survive in the lab as long as embryonic stem cells. Many researchers believe that both embryonic and adult stem cells should be studied because it is unclear now which will ultimately be the most useful in medicine.
