Since the 1970s, patents on human genes and genetic diagnostic methods have been granted under the assumption that they stimulate the development of diagnostic methods and therapeutic products. However, the principles and practices of patenting vary between jurisdictions. Do patent holders, researchers, clinicians and patients really benefit from this heterogeneous patent system? We discuss the problems that result from the current system and suggest how they might be solved by altering the way in which patents are granted and/or licensed.