What are Stem Cells?

Stem Cells are defined as cells which meet 3 criteria:

1. They keep renewing themselves by dividing to make more Stem Cells.
2. Stem Cells are not specialized: they don’t have a specific task in the body.
3. Under the right conditions, Stem Cells will differentiate: They will divide to make one Stem Cell plus one cell which is more specialized. In this manner an initial collection of stem cells can evolve into many different types of specialized cells.

The US National Institute of Health (NIH) has an excellent website devoted to explaining Stem Cell information.