Ethicists contend that researchers are obliged to report genetic research findings to individual study participants when they are clinically significant, that is, when they are clinically useful or personally meaningful to participants. Yet whether such standards are well understood and can be consistently applied remains unknown. We conducted an international, cross-sectional survey of cystic fibrosis (CF) and autism genetics researchers using a quasi-experimental design to explore factors influencing researchers' judgments. Eighty percent of researchers agreed, in principle, that clinically significant findings should be reported to individual participants. Yet judgments about when a specific finding was considered clinically significant or warranted reporting varied by scientific factors (replication, robustness, intentionality, and disease context), capacity of the research team to explain the results, and type of research ethics guidance. Further, judgments were influenced by the researchers' disease community (autism or CF), their primary role (clinical, molecular, statistical) and their beliefs regarding a general reporting obligation. In sum, judgments about the clinical significance of genetic research results, and about whether they should be reported, are influenced by scientific parameters as well as contextual factors related to the specific research project and the individual researcher. These findings call into question the assumption that the conditions under which an obligation to disclose arises are uniformly understood and actionable. Adjudicating the clinical readiness of provisional data may be a responsibility better suited to evaluative experts at arms' length of the provisional data in question, rather than a responsibility imposed upon researchers themselves.