There are many reasons experimenters decide to self-test, but amongst the most fundamental is the ethical principle that the experimenter should not subject the participants in the experiment to any procedure they would not be willing to undertake themselves. This idea was first codified in the Nuremberg Code in 1947, which was a result of the trials of Nazi doctors at the Nuremberg trials accused of murdering and torturing victims in valueless experiments. Several of these doctors were hanged. Point five of the Nuremberg Code requires that no experiment should be conducted that is dangerous to the subjects unless the experimenters themselves also take part. The Nuremberg Code has influenced medical experiment codes of practice around the world, as has the exposure of experiments that have since failed to follow it such as the notorious Tuskegee syphilis experiment.