Trust is taken to be one of the foundational values in the doctor-patient relationship, facilitating access to the benefits of health care and providing a guarantee against possible harms. Despite this foundational role, some doctors betray the trust of their patients. Trusting involves granting discretionary powers and makes the truster vulnerable to the trustee. Patients trust medical practitioners to act with goodwill and to act competently. Some patients carry pre-existing vulnerabilities, for reasons such as gender, poverty, age, ethnicity, or disability, (...) and these vulnerabilities can be exacerbated when such patients extend their trust to a doctor. Gender stereotypes reduce women's ability to challenge and thereby assess their doctor's competency. In addition, women are more likely to be distrusted by their doctors and have their experiences of medical symptoms discounted. In this paper, we analyze two extreme examples of breaches of medical trust that exploited the vulnerability of women in the health care system: the "unfortunate experiment" at the National Women's Hospital in New Zealand and the Harold Shipman murders of elderly patients in the United Kingdom, examining the potential role of gender in the outcomes with regard to trust. Major breaches of medical trust such as these typically lead to government inquiries, revisions of ethical guidelines, and substantive policy change in an effort to re-establish public and patient trust. We argue that the medical profession has an ethical obligation to put mechanisms in place to protect vulnerable patients from abuses of trust, to monitor colleagues' competence, and to be prepared to blow the whistle to protect patients who are not in a position to recognize misplaced trust. Such mechanisms will act disprosportionately to reduce harm to women as patients. (shrink)