Medical ethics is an interdisciplinary science, which deals with ethical problems and issues in the field of medical sciences. These issues are regarded as professionalism, ethics in medical research and healthcare policy-making. Contents of this topic have entered medical ethics from different fields of knowledge and human knowledge involved in this area. It incorporates a variety of sciences and human knowledge, notably ethics philosophy, law, theology, jurisprudence, literature, sociology, psychology, economy, and history. Some problems and issues in this field have a long history and have been considered in old medical contexts. Some of these issues include abortion and patient-physician relationship. On the other hand, some of the current issues have been raised in the modern world due to the unprecedented capabilities given to human by modern science and technology, including organ transplantation and use of stem cells in treatment of diseases. Some of the medical ethics matters include ethical issues in in end-of-life patients, ethics in medical research, duties and responsibilities of physicians to patients, rights and role of patients in medical decision-making, beneficence and nonmaleficence in health care, legal and ethical issues in organ transplantation, fairness in the distribution of resources, informed consent, euthanasia, health and illness, concepts of person and personhood, human dignity, moral status, ethical issues in fertility and infertility, brain death and its criteria, human cloning, patient competency and its assessment tools, principle-based approach, pattern-based approach (casuistry), results-based approach (consequentialism), narrative-based approach (narrativism), care-based approach, animal research, task-oriented approach, and ethics in policy-making.