The answer is in the wake of the atrocities committed by soldiers in Nazi Germany. In addition, investigation of the participants in Milgram's obedience study has specified that which personality trait was highly associated with the willingness to be obedient. The naive subjects in the Stanley Milgram experimentation were given the chance to administer shocks to destitute victims. The thoroughgoing voltage that could be coped in one shock is 450.
The correct answer is permit
In almost all cultures it is forbidden to have relationships within an intimate kinship group. Incest is not accepted in most cultures. Cases are not legitimized and, when they occur, individuals are penalized.
But in some cultures incest is allowed and there is no punishment or way to outlaw the practice.