Stem cells can divide to produce new cells, which can then divide into different cell types. They therefore have the potential to be transplanted into patients to treat medical conditions and disease. They could be used to replace cells that have been damaged or destroyed, eg:
The stem cells used could be:
Embryonic stem cells can differentiate into a wider range of cell types, but are difficult to obtain. The best source is a five-day-old embryo, although there are clinical, ethical and social issues with their use.
Adult stem cells will differentiate into a narrower range of cell types. Bone marrow transplants are an example of adult stem cell transplant. Bone marrow cells will differentiate into different types of blood cell. Bone marrow transplants are carried out: