At the heart of research with human beings is the moral notion that the experimental subject is altruistic, and is primarily concerned for the welfare of others. Beneath the surface, however, lies a very different ethical picture. Individuals participating in potentially life-saving research sometimes take on considerable risks to their own well-being. Efforts to safeguard human participants in clinical trials have intensified ever since the first version of the World Medical Association's Declaration of Helsinki (1964) and are now codified in many national and international laws and...