In 1991, Duke University funded a study to see why the head of a man's penis was larger than the shaft. After one year and $180,000, they concluded that the reason the head was larger than the shaft was to give the man more pleasure during sex.
After Duke published the study, Stanford decided to do their own study. After $250,000 and 3 years of research, they concluded that the reason was to give the woman more pleasure during sex.
Louisiana State University, unsatisfied with these findings, spent $19.27 (for a Playboy, a Penthouse, and a case of Milwaukee's Best) and in less than 2 hours concluded that it was to keep a man's hand from flying off and hitting him in the forehead.