 Stem cells are unspecialized cells in the body that do not have a specific function yet for example, they have not become heart cells or brain cells yet. Stem cells are able to divide and develop into more mature, function-specific cells and take the place of those cells that die, are injured or can no longer function the way they are supposed to. Stem cells are being studied a lot because of this ability and there is the possibility that they may be used to take the place of cells that are no longer working in different parts of the body because of disease as in cancer, diabetes, and heart disease. Stem cells can be found throughout the body, but they are most common in the bone marrow, the thick, spongy material inside the bones. 