ABO blood group system During the 1930s, connecting blood groups to personality types became popular in Japan and other areas of the world. Studies of this association have yet to confirm its existence definitively. Other popular but unsupported ideas include the use of a blood type diet, claims that group A causes severe hangovers, group O is associated with perfect teeth, and those with blood group A2 have the highest IQs. Scientific evidence in support of these concepts is nonexistent. ABO blood group system The ABO blood group system is used to denote the presence of one, both, or neither of the A and
Jehovah's Witnesses and blood transfusions was released, outlining Jehovah's Witnesses' general doctrine on blood. In 2000, the Watch Tower Society's stand on blood fractions was clearly stated. Members were instructed to personally decide if accepting a fraction would violate the doctrine on blood. In a later article, members were reminded that Jehovah's Witnesses do not donate blood or store their own blood prior to surgery. In May 2001, the Watch Tower Society revised its medical directives and identity cards addressing its doctrinal position on blood; the revised materials were distributed from May 3, 2001. These revised documents specified that "allogeneic blood transfusions" were unacceptable whereas