A cell from which a variety of other cells can develop through the process of cellular differentiation. Stem cells can produce only a certain group of cells (as with skin stem cells) or any cell in the body (as with embryonic stem cells).
A major controversy involves the question of whether nonembryonic stem cells should be used for medical purposes.
An unspecialized cell found in fetuses, embryos, and some adult body tissues that has the potential to develop into specialized cells or divide into other stem cells. Stem cells from fetuses or embryos can develop into any type of differentiated cells, while those found in mature tissues develop only into specific cells. Stem cells can potentially be used to replace tissue damaged or destroyed by disease or injury, but the use of embryonic stem cells for this purpose is controversial. Also called progenitor cell.