"No Clowning for Hospitalized Kids"
60-Second Science from Scientific American podcasts
January 17, 2008

Researchers spoke to 255 kids between the ages of 4 and 16.  And none of them liked clowns. 

According to the magazine Nursing Standard, one researcher said, “We found that clowns are universally disliked by children. Some found them frightening and unknowable.”