Biomedical research is the lifeblood of military medicine. Issues relating to the potential vulnerability of "captive subjects", in the acquisition of new knowledge of biomedical import in the military domain, remain topical. The Australian Defence Medical Ethics Committee (ADMEC) is a mixed civilian- military Committee of the Defence Health Service within the Australian Defence Force and is one of two national service-civilian committees chaired by the Surgeon General. A recent survey of the members of that Committee have identified ten key themes in the analysis of any potential biomedical research in which approaches are made servicemen and women as potential volunteers. These themes include an ethos of what both society and the military domain might consider "allowable risk"; the quantification of risk for potential volunteers, special issues of privacy and confidentiality within the institutions of the military domain; special issues of "informed consent"; the monitoring of research; and questions relating to free and informed consent. There are many examples of groups who comprise the ethical class of "captive subjects" but servicemen and women are unique in that influences upon individuals to participate in biomedical research render them potentially "captive" not only from vertical, but internal and lateral (peer) pressure as well. A heightened awareness of the concept of "captive subjects" in the bioethical sense remains an essential tool not only for researchers in the civilian and military domains but for members of the broader society which rightly demands that "free and informed consent" is a research axiom.