In an earlier paper in this Journal, we examined the fundamental principles of negligence and the approach taken in recent Australian decisions in setting out boundaries to any categorisation of a fiduciary relationship between doctor and patient. In this paper we focus on the scope of the doctor-patient relationship and the extent of the medical practitioner's duties in this relationship. The boundaries of the medical relationship have raised a number of important ethical and legal concerns. For example, does a patient have a right of access to his or her medical records on the basis of a fiduciary relationship that exists between the doctor and the patient? Our contention in this paper is that the scope or boundaries of the fiduciary relationship duties owed by medical practitioners will become even more significant in view of recent developments in genetic testing. Genetic testing allows the medical profession to determine if a pre-disposition to develop disease exists prior to the onset of such symptoms as breast and ovarian cancer. However, this raises the central issue as to who should have control of these records of diseased people. Will a plaintiff be able to rely on a doctor's fiduciary duty to his or her patients in order to gain access to genetic records? It will be further suggested that genetic technology also raises important ethical and legal issues of confidentiality and discrimination. A situation may increasingly become common where commercial organisations screen clients or customers on the basis of their genetic susceptibility to diseases or a particular medical condition. In this context, we focus attention on the insurance industry and address the question as to whether insurers can refuse insurance on the basis of a genetic predisposition to a particular condition or disease. These issues will undoubtedly become major aspects of litigation in the future. In this paper, we attempt to develop the doctrine of fiduciary duties to deal with these unresolved issues and potential future causes of action.