Some individuals are highly susceptible to disease caused by chemical exposures and this hypersusceptibility can be genetically determined. Because biomarker technology for the determination of genetic predisposition is at the disposal of researchers, the capability therefore exists to include genetic screening in epidemiologic studies. The application of this technological advance in population-based research is, however, fraught with ethical tensions heretofore unknown. Moral duties alone are of limited use in resolving these problems. Scientific documentation is almost always insufficient to clarify the exact nature of the ethical implications, and ways to deal with uncertainties arising as a result of information generated from genetic screening studies must be considered. The most important tensions relate to autonomy and the right to privacy, fairness and equality, while balancing potential public interest in paternalistic measures. Because no moral framework has been accepted for dealing with this technological advance, an ethical discourse in an open forum is required with all affected parties. Scientists alone, or any other group in isolation, should not expect to resolve these questions, but they should participate in and facilitate the process.