Bone marrow transplantation is a medical procedure that involves stem cell transplantation. The common feature of recipients is a need for blood stem cells. Most recipients are leukemia patients or others who have been exposed to high doses of chemotherapy or total body irradiation resulting in destruction of their bone marrow stem cells. Other patients who receive bone marrow transplants include pediatric cases where the patient has an inborn defect such as severe combined immunodeficiency or congenital neutropenia and was born with either no blood stem cells or defective stem cells. Other conditions that bone marrow transplants are considered for include thalassemia major, sickle cell disease and aplastic anemia.