Euthanasia refers to intentionally ending a life to relieve suffering. It has ancient roots but was condemned for over 2000 years. In the early 20th century, some argued for "mercy killing" those deemed worthless. Euthanasia may be voluntary, non-voluntary, or involuntary depending on patient consent. It is legally permitted in a few U.S. states and countries but generally banned due to ethical and practical concerns about the sanctity of life and potential for abuse. Proponents argue it respects patient autonomy while opponents fear it could devalue human life.