Objective: To examine the relative importance of factors influencing health insurers' coverage of new genetic technologies.

Methods: A national survey in which the decision makers for private health insurers were asked whether they would cover cystic fibrosis (CF) carrier screening, testing for genetic susceptibility to breast cancer (BRCA test), and medical costs of a clinical trial of gene therapy for CF under a variety of conditions.

Results: Respondents' coverage of the two tests and of medical costs of clinical trials was low at the time of the study (4%–15.5% of insurers.) Their coverage of CF carrier screening and BRCA testing would be increased significantly if the group tested was restricted to those at high risk, if detection rates were higher and costs lower, and if testing was endorsed by a national professional group or consensus conference. Coverage of the medical costs of a trial of CF gene therapy would be significantly more likely if the trial was restricted to children or adults with severe CF, safety and effectiveness was proven, and therapy could be administered in a regional hospital or an outpatient setting rather than in a research hospital.

Conclusions: Health insurers play a critical role in the diffusion of new genetic technologies. The validity of genetic tests and the safety and effectiveness of new therapies are primary factors influencing health insurers' coverage. Lower costs and approval of professional groups are other factors associated with increased coverage.