Severe aplastic anemia is characterized by severe deficiencies in peripheral-blood platelets, white cells, and red cells. These defects in mature cells occur because aplastic bone marrow contains severely reduced numbers of hematopoietic stem cells. To date, Hematopoietic stem cell (HSC) transplants are routinely used to treat patients with many different diseases, including various cancers and blood disorders, such as aplastic anemia. The main sources of HSCs are bone marrow, cord blood and peripheral blood. However, challenges include obtaining enough functional HSCs to ensure optimal engraftment, and avoiding immune rejection and other complications associated with allogeneic transplantations. Novel abundant sources of clinical-grade HSCs are therefore being sought.