Attempts to establish ethical standards for the practice of medicine go back at least as far as the English physician Thomas Percival (1740-1804) and much farther. These efforts have been compounded many times over by the escalating growth in biomedical research and clinical investigation in recent years. Awareness and concerns have arisen over the introduction of new technologies and advances in biomedical research and clinical investigation. Reflecting these concerns has been the growth of the discipline of medical ethics, which attempts to find a delicate balance between practical considerations and ethical values, without unnecessarily restraining progress in biomedical research and investigation.