 Proponents might avoid this dilemma by assuming that individuals behind the veil of ignorance will make decisions based purely on self-interest, unconstrained by moral limits or considerations. Presumably, many different systems would satisfy this requirement. In particular, the system that produces the greatest amount of benefits overall may well be one that we regard as unethical. Many endorse the view that clinical research studies which offer no potential benefit to participants and pose a high chance of serious risk, such as death, are unethical, independent of the magnitude of the social value to be gained. For example, almost all research ethicists would regard as unethical a study which intentionally infects a few participants with the HIV virus, even when the study offers the potential to identify a cure for AIDS. Yet, individuals behind the veil of ignorance who make decisions based solely on self-interest might well allow this study on the grounds that it offers a positive cost-benefit ratio overall: the high risks to a few participants are clearly outweighed by the potential to save the lives of millions.