The current discussion over the use of embryonic stem cells for research has two main components. The first component is comprised of the serious ethical and moral issues raised by the use of discarded embryos. The second component is the potential benefit of this research. Setting aside the ethical issues for discussion at another time and place, what I want to explain here is the true potential of stem cells.
The process of the construction of what eventually becomes a fully-formed human being begins with a single cell formed by the joining of an egg and a sperm cell. That cell divides to become two cells, those cells divide, and so on. After 4 or 5 days, at the blastocyst stage, the mass consists of about 100 cells, more or less. The inner cells of this blastocyst are what we call stem cells. At this stage, these cells are undifferentiated and can develop into any of the more than 200 distinct types of cells that make up a human body. This point is crucial to understanding the true potential of stem cells. They can potentially produce any type of cell. Heart, liver, bones, skin, eyes, teeth, red blood cells-all of the myriad components of cells and tissues and organs that make a viable human being arise from stem cells.
Even respected scientists have consistently downplayed what might result from research done with these cells. The focus, at least in public media, has been on the potential to improve treatments of some serious diseases, especially Alzheimer's and Parkinson's. Those are terrible ailments and it would indeed be wonderful to improve the prospects of those who are afflicted with these diseases. But to concentrate on that betrays a fundamental misunderstanding of what stem cells are and what they can do.
These cells can produce a new and hopefully healthy copy of any part of the body. Research into stem cells and how they work could lead to a result far more dramatic than improving treatment of a couple of diseases, even diseases as devastating as Alzheimer's and Parkinson's. The possibility exists that any damage to a person's body, whether caused by illness or injury or the deterioration that hitherto has been the inevitable result of aging, could be repaired by growing new cells and replacing whatever has been damaged with healthy tissue. If a hip deteriorates because of arthritis and bone loss, replace it. Not the way it is done today, with high-tech but non-human materials, but with another new, strong hip joint made of the same material as the original. If someone loses three fingers in an industrial accident, teach his body to grow new fingers instead of having to struggle with a prosthesis. No more dentures, no more toupees. The average human lifespan could change from the threescore and ten with which we are familiar to a term that is measured in centuries. And all of those years could be lived in a strong and healthy body. It would be the greatest change in the human condition since we stopped walking on all fours and stood upright.
That is the real potential of stem cells.