PurposeAs genome sequencing moves from research to clinical practice, sequencing technologies focused on “medically actionable” targets are being promoted for preventive screening despite the dearth of systematic evidence of risks and benefits and of criteria for selection of screening subjects. This study investigates researchers’ and research participants’ perceptions of these issues within the context of a preventive genomic screening study, GeneScreen.MethodsWe recorded researcher deliberations regarding age eligibility criteria and the risks and benefits of screening, and conducted interviews with 50 GeneScreen participants about their motivations for joining and their perceptions of risks and benefits.ResultsResearchers made assumptions about who would want and benefit from screening based on age. After discussion, researchers opted not to have an upper age limit for enrollment. Participants of all ages perceived similar benefits, including prevention, treatment, and cascade testing, and similar risks, such as insurance discrimination and worry.ConclusionWhile clinical benefits of preventive genomic screening for older adults are debatable, our respondents perceived a range of benefits of screening in both clinical and research settings. Researchers and clinicians should carefully consider decisions about whether to exclude older adults and whether to provide information about benefits and risks across age groups.GENETICS in MEDICINE advance online publication, 7 December 2017; doi:10.1038/gim.2017.206.