 Stem cells can develop into every cell, every tissue and every organ in the human body, e.g., they can make any kind of cells in the human body. Stem cells reproduce themselves many times over and over. Their almost limitless potential has made stem cells a significant focus of medical research. But before scientists can use stem cells for medical purposes, they must first learn how to harness their power. They cannot treat disease until they learn how to manipulate stem cells to get them to develop into specific tissues or organs. 