Astrology

A large-scale test of persons born less than five minutes apart found no hint of the similarities predicted by astrology. As a counter argument, some astrologers argue that a birth just a minute apart can make all the difference by altering what they call the 'house cusps;' naturally they don't worry about such levels of precision when performing their own evaluations, they'll just take what they can get.

An article from the Washington Times describing the study:
http://www.washtimes.com/world/20030817-105449-9384r.htm

and...

The actual study published in the Journal of Consciousness Studies in 2003:
www.imprint.co.uk/pdf/Dean.pdf