Unequal treatment of human research subjects is a significant ethical concern, because justice in research involving human subjects requires equal protection of rights and equal protection from harm and exploitation. Disputes sometimes arise concerning the issue of unequal treatment of research subjects. Allegedly unequal treatment occurs when subjects are treated differently and there is a genuine dispute concerning the appropriateness of equal treatment. Patently unequal treatment occurs when subjects are treated differently and there is not a genuine dispute about the (...) appropriateness of equal treatment. Allegedly unequal treatment will probably always occur in research with human subjects due to disagreements about fundamental questions of justice. The best way to deal with allegedly unequal treatment is to promote honest and open discussions of the issues at stake. Research regulations can help to minimize patently unequal treatment by providing rules for investigators, ethical review boards, institutions, and sponsors to follow. However, patently unequal treatment may still occur because the regulations are subject to interpretation. Federal agencies have provided interpretive guidance that can help promote consistent review and oversight of human subjects research. Additional direction may be needed on topics that are not adequately covered by current guidance or regulations. International guidelines can help promote equal treatment of human subjects around the globe. While minor variations in the treatment of research subjects should be tolerated and even welcomed, major ones (i.e. those that significantly impact human rights or welfare) should be avoided or minimized. (shrink)