Bioethics is the study of moral issues in fields of medical treatment and research. This term is also sometimes used more generally to describe ethical issues in life sciences and the distribution of scarce medical resources. The professional fields that deal with ethical issues in medicine include medicine, nursing, law, sociology, philosophy, and theology, though in the late 20th century medical ethics has come to be recognized as its own practice.
Medical ethics started with several early codes of ethics. One of the best known is the ancient Greek Hippocratic Oath, which required physicians above all to "do no harm."" There were also professional codes of ethics such as the one written by English physician Thomas Percival in the 18th century that provided a foundation for the first code of ethics established in 1846 by the founders of the American Medical Association. The Nuremberg Code for research ethics on human subjects was established during the war crime trials at the close of World War II in response to the heinous abuses in human experimentation performed in Nazi Germany. The approach of new medical and reproductive technologies after the 1950s further complicated the moral and societal issues of medical research and practice. .
In 1966 Henry Beecher, a well-known physician at the Harvard Medical School, published an important paper reporting many different abuses of human subjects in medical research at major universities and medical centers in the United States. The ethical violations he spoke of included the use of subjects without their consent and the participation in medical research of subjects who have not been offered the option of standard treatment. Beecher's article triggered discussions and debate inside and outside of medicine about the importance and practicality of obtaining consent from research subjects or surrogates if the subjects could not provide consent for themselves.