Unfortunately, history has revealed many prominent examples of research involving questionable and immoral ethics and practices. As these atrocities were disclosed, ethical codes and regulations were developed. The two most well-known catalysts for these changes were the Nazi War Crimes Tribunal and the Tuskegee Syphilis Study.
Following World War II, leading Nazi doctors were brought to justice before the International Military Tribunal at Nuremberg. Twenty doctors were charged with War Crimes and Crimes Against Humanity. The Nuremberg trial of doctors, which began in 1946, revealed evidence of sadistic human experiments conducted at the Dachau, Auschwitz, Buchenwald and Sachsenhausen concentration camps. Subsequently, in 1947, the Nazi War Crimes Tribunal issued the Nuremberg Code, which was the first internationally recognized code of research ethics. (http://www.hhs.gov/ohrp/references/nurcode.htm)