 A few commentators (Caplan 1984; Harris 2005; Heyd 1996) try to justify exposing research participants to risks for the benefit of others by citing an obligation to participate in clinical research. At least all individuals who have access to medical care have benefited from the efforts of previous research participants in the form of effective vaccines and better medical treatments. One might try to argue that these benefits obligate us to participate in clinical research when its our turn.