Genomics researchers struggle with the issue of returning individual research results to participants because, in many if not most cases, the results are of uncertain meaning or significance and thus may lead to misunderstanding, confusion, and harm when participants attempt to make clinical sense of them. Return of incidental findings poses similar but not identical problems. The provision to an individual participant of data that pertain to him or her but are not directly related to the objectives of the study may not raise uncertainty issues when deemed important enough to return. Nonetheless, the expectation that some clinically meaningful information will be identified in genomic research contributes to the blurring of research and clinical care.