One Chance in a Million: Altruism and the

patients who suffer from leukemia or other blood diseases, a stem cell transplant fre-quently offers the best chance of survival. Such a transplant is likely to be a life saving event. According to the Web site of the London Health Sciences Centre (2006): “Long-term survival may be greater than 80 per cent, … depending on the type of disease treated, the patient’s age, and the severity of illness. For patients with acute leukemia, long-term survival is 50–60 per cent but this is much better than 20–25 per cent survival when patients are treated with chemotherapy alone. … recipients eventually return to a normal lifestyle.” The most effective treatment for many blood diseases is radiation that destroys all blood cells in the body, both diseased and healthy. The blood cells must then be replaced with healthy ones. This is accomplished by transplanting blood-forming stem cells from a healthy donor whose immune system is compatible with that of the recipient. One’s best prospect for a donor is a brother or sister. The probability that two siblings are acceptable matches is one-fourth. Those who lack a sibling donor must search among the population at large. Finding a compatible stem cell donor is vastly more difficult than finding a blood donor. The probability that two randomly selected white Americans are of matching type is less than one in 10,000. About 20 percent of white Americans are of types that are shared by less than one person in a million. The African American population is genetically even more diverse. The probability that two randomly selected African Americans will match is less than one in 100,000