Blood donation bag. Gloved hands holding a plastic bag containing blood. This blood was taken from the umbilical cord of a pregnant woman, and may be used in transfusions to treat leukaemia and other disorders of the immune system. The blood is collected from the umbilical cord immediately after the mother has given birth. Umbilical blood is useful because it contains a high number of stem cells which divide to form healthy new cells; stem cells are found only in bone marrow in adults. Umbilical blood is also less likely to be rejected by the new host. Photographed at the Milan Cord Blood Bank in Italy.