Stem cells are able to divide and differentiate into specialized cell types and are capable of making more stem cells, as well. Embryonic stem cells are found in the inner cell mass of a blastocyst, a stage in embryonic development. These embryonic stem cells can differentiate into any of the body's specialized cells. When a child is born, the umbilical cord blood is an additional source of stem cells. Adult stem cells are found in many organs and allow for the repair of tissues. Adult stem cells are found in the bone marrow, for example, in the femur. They are also found in the blood but must be extracted from the blood in order to harvest them. They can be found in lipid cells which are the fat cells in the body. Stem cells are now and promise to be an important source of future medical therapies.