AMHERST, N.Y. (January 13, 2006)-Friday the 13th is always a stressful day for friggatriskaidekaphobes-people with an overwhelming fear of Friday the 13th. (The term has its origins in Nordic mythology-the goddess Frigga is the namesake of the sixth day of the week-and ancient Greek-triskaideka means "thirteen.") According to a 1996 Gallup poll, 9 percent of Americans, (about 26.5 million people) say they are superstitious about the number 13...

...How did thirteen get such a bad reputation? To understand, one needs to know the history of twelve, says CSICOP Senior Research Fellow Joe Nickell. "The number twelve has traditionally represented completeness in mythologies and religions around the world," says Nickell. "There are twelve months of the year, twelve chief gods of Olympus, twelve signs of the zodiac, and twelve apostles of Jesus. Thirteen exists just one digit beyond twelve, and is symbolic of the first departure from divine completeness or the initial step towards evil."

Friday has an equally bad history, Nickell points out. According to some traditions, Eve gave the apple to Adam on Friday, the great flood began on a Friday, the Temple of Solomon was destroyed on a Friday, execution day was Friday in ancient Rome, and Good Friday exists because it is the reported day of Jesus' crucifixion. An English schoolboy allegedly proved mathematically that thirteen, when examined over a 400-year period, falls on Friday more than any day of the year. (He was thirteen years old at the time, of course.)

Yet the number 13 has a lesser-known role as a lucky number: At the birth of our nation, thirteen colonies formed the original United States of America, a baker's dozen is considered a fortunate bargain, and if you are Jewish, age thirteen is your lucky time for a bar or bat mitzvah.