The rapidly growing number of disease gene patents--patents that claim all methods for diagnosis of a particular genetic condition--threatens the ability of physicians to provide medical care to their patients. In the past, patented diagnostic tests were made broadly available to the medical community in the form of test kits or licenses to use the patented test. Disease gene tests, however, are being monopolized by a small number of providers. Monopolization of medical testing services: (a) threatens to restrict research activities; (b) creates unacceptable conflicts of interest; (c) may reduce patient access to testing; (d) may lead to inequitable extensions of patent terms on tests and related discoveries; and (e) grants to patent holders the ability to dictate the standard of care for testing, and to otherwise interfere with the practice of medicine. Because of the risks raised by monopolization, amendment of the patent law to require compulsory licensing of physicians providing medical services is recommended.