As the scientific study of genetic variation between human groups gains momentum around the world, traditional questions of research ethics are being transformed in ways that challenge our conventional wisdom about the responsible conduct of research. Challenges associated with obtaining informed consent may be heightened because of difficulties explaining genetic concepts cross-culturally. In some cases, language barriers may diminish effective communication even when literal translation is not a problem. Genetic researchers conducting family studies may encounter notions of kinship and lineage that are inconsistent with genetic science and under which even the scientific depiction of a family "pedigree" may be obscure. Questions pertaining to decisional authority are exacerbated when investigators view entire groups or populations as their "subjects." In this case, the issue of community representation and the delegation of authority to make decisions for participation in genetic research are socially and politically complex. In multi-national genetic studies, simply transferring standard methods from industrialized societies, which depend heavily on obtaining written consent, is inadequate, but no reasonable alternatives have yet been developed. A reformulation of the fundamental approach to informed consent for genetic epidemiological research is needed to accommodate the scientific need for information on sequence variation, to foster the development of effective clinical intervention, and to improve access to health care for all ethnic populations. Building on our current research (1 R01-HG-02207-01), the proposed study has four primary goals: 1) to develop, test, and implement a videotaped educational intervention to improve informed consent for genetic epidemiological research on hypertension and breast cancer being conducted with populations of African heritage in the U.S. and Nigeria; 2) to conduct a randomized trial to test the effect of the videotaped educational intervention on two specific outcomes: a) comprehension of research goals; and b) participation during the informed consent discussion, as measured by the number and quality of questions asked; 3) to examine beliefs about the implications of genetic research for personal health and individual and group identity, and determine their influence on individuals' willingness and motives to participate in genetic research; 4) to develop recommendations to improve informed consent procedures for genetic epidemiological research to ensure that they are culturally appropriate, maximally informative, and protective for ethnically diverse populations. The proposed study represents the first transnational attempt to evaluate a videotaped educational intervention for informed consent in genetic epidemiological research. Moreover, results of this study have the potential to contribute to the growing literature on the meaning of genetic research for individuals and communities of African heritage.