Some people have brains that will function properly over the course of a lifetime while others have structures that are prone to breakdown, as in the case of Parkinson's disease which leads to deterioration of muscle control. Much like changing the oil and oil filter in a car when they get too old, we too may be able to swap sections of our body that have worn out. One current treatment for Parkinson's disease is prescribing a drug called L- Dopa which can help to alleviate, but not completely eliminate the symptoms of the disease. Furthermore, a patient with the disease is faced with taking the drug every day, which can be inconvenient or even dangerous if he or she forgets to take the drug. Our bodies are made of trillions of cells, each of which has a specific structure and function.
Humans have muscle cells, brain cells, liver cells, etc.
Someday, to cure diseases like Parkinson's we may simply be able to replace the defective cells in the brain with stem cells. Once the stem cells are placed inside the brain, they could be transformed into properly functioning versions of the defective brain cells. The miracle of stem cells may sound too good to be true, but the technology to properly harvest and use stem cells in within our reach. Although the curative properties of stem cells are remarkable and the potential to help many individuals is astounding, many ethical issues surround the production and collection of stem cells. Each adult human body contains stem cells, albeit not very many.