There are curious cases of people who feel no pain or have extreme resistance to discomfort. These individuals are often studied by researchers who hope to develop better methods of pain management. One such woman was discovered after she recovered from a highly painful wrist surgery using Tylenol alone. As researchers at the University College of London found out, she had a history of this sort of endurance, and it appeared to have been passed on to her son. With her consent, they ran genetic tests, identifying two mutation in genes related to FAAH.