TOKYO -- To many Japanese, the key to their personality lies not in their stars but in their blood type. Type A's, they believe, are perfectionists and make good accountants; Type B's are sociable but selfish.
Now one of Japan's favorite pop beliefs is running into accusations of abuse and discrimination, with critics saying it is being used to assign jobs, match couples, even pigeonhole schoolchildren.
Irate scientists are attacking the theory in books and Web pages. Magazines are examining the debate in articles with titles like, ''Don't bully Type B."
The debunkers point out that blood type is determined by the proteins in the blood -- hardly a determinant of character. ''It's mere superstition," says Tatsuya Sato, a professor of psychology at Ritsumeikan University.
Ryoichi Kikuchi of the Broadcasting Ethics and Program Improvement Organization, says his watchdog group has fielded hundreds of complaints.
''Viewers are now complaining about their children being bullied at school, couples breaking up, and bosses treating underlings unfairly -- all because of blood type prejudice," he said.
Newspaper polls show only 20 percent of Japanese say they're convinced that blood type influences personality. But the theory, imported from its Nazi supporters and adopted by Tokyo's militarist government in the 1930s, is highlypopular nonetheless.
The craze faded in the 1930s as its unscientific basis became clear. But it was revived in the 1970s with a book by Masahiko Nomi, an advocate and broadcaster with no medical background. His son, Toshikata, heads a private group called the Human Science ABO Center and stands by the theory.
Sakumi Itabashi, a professor and author of ''The Myth of Fortunetelling," blames the craze on a national passion for efficiency and order. ''People want to find a rule in everything, including personality, because that makes things more predictable and they feel more secure," he said.