Healthy volunteer registries and ethical research principles.

The dual enrolling of phase I volunteers is a potential risk to subjects. It can also distort study results, threaten study validity, and possibly cause harm to future patients. Existing subject registries differ in structure, funding, and governance. Although the choice of the ideal system is driven by the scope of the risk and the funding mechanism, and is ultimately a value judgment of freedom versus paternalism, none of the registries significantly impinges on the tenets of ethically based research.