Studies of human embryonic stem cells may yield information about the complex events that occur during human development. Researchers believe that stem cell therapy has the potential to radically change the treatment of human disease. A number of adult stem cell therapies already exist, particularly bone marrow transplants that are used to treat leukemia. In the future, medical researchers anticipate being able to use technologies derived from stem cell research for generation of cells and tissues that could be used for cell-based therapies. Today, donated organs and tissues are often used to replace ailing or destroyed tissue, but the need for transplantable tissues and organs far outweighs the available supply. Stem cells, directed to differentiate into specific cell types, offer the possibility of a renewable source of replacement cells and tissues to treat diseases including Parkinson's and Alzheimer's diseases, spinal cord injury, Cerebral stroke, burns, Multiple Sclerosis, Motor Neuron Disease, Duchenne's muscular dystrophy, ischemic heart disease, diabetes mellitus, Critical Limb Ischemia, vision and hearing loss, osteoarthritis, rheumatoid arthritis and many more.
Some of the most serious medical conditions, such as cancer and birth defects, are due to abnormal cell division and differentiation. A better understanding of the genetic and molecular controls of these processes may yield information about how such diseases arise and suggest new strategies for therapy.
Human stem cells could also be used to test new drugs. For example, new medications could be tested for safety on differentiated cells generated from human stem cell lines. Cancer cell lines, for example, are used to screen potential anti-tumor drugs. But, the availability of pluripotent stem cells would allow drug testing in a wider range of cell types.