Blood transfusion is an important therapy even at the developed present medicine. The main problems impeding progress in blood transfusion are the inconsistency of supply and the risk for infection of various microorganisms. Therefore, increased interest in the use of human stem cells has emerged following significant progress in ongoing stem cell biology research to procure a large quantity of safe blood for therapeutic transfusion. Although it is at present not possible to predict which types of stem cells will be best suitable for the efficient production of erythrocytes, the isolation of human embryonic stem cells and the discovery of adult stem cells (tissue stem cells) taken together give substance to hopes that novel principles may be developed in the procuration of blood cells for transfusion. To achieve this, however, we have to solve a number of technical and ethical problems.
