The advances made in the use of adult stem cells could not have been projected five years ago but the difficulties in using them should not be minimised and progress in the field may have to match similar progress in embryonic stem cell research. For example, adult stem cells do not exist together similar to embryonic cells. They are scattered all over an organ and they can be difficult to collect for use in a practical manner. Stem cells are in good supply, for example, in the brain but they are difficult to collect because the best ones are to be found in a part of the brain known as the substansia nigra. This is located deep in the brain and I am at a loss as to how they can be taken from a living adult. They can be harvested from the brains of the recently deceased but these cells die rapidly due to a lack of oxygen. While they are useful when harvested from the living brain, there are difficulties when they are harvested from the recently deceased in a similar manner to the harvesting of vital organs that give hope to transplant patients. This issue must be addressed.