A Silicon Valley gene-testing startup is responding to criticism that the tests could spur bad health-care choices by teaming up for a broad study of how the results affect behavior. Navigenics charges customers $2,500 to analyze their DNA to assess their risk of developing more than 20 diseases. Several public health officials have said the science on which the tests by Navigenics and other companies are based is too new to be used for making serious medical decisions.
