The Coolidge Effect

This is just a principle of evolutionary biology that everybody ought to know, based on a funny anecdote:

Supposedly, one day Mr. & Mrs. Coolidge were doing a publicity tour of a farm, going around and being shown all the cool things while making a statement about agriculture. At one point, the couple got separated. A farmer, bold as brass, shows off the prize rooster to Mrs. Coolidge, boasting that it can have sex dozens of times a day. Mrs. Coolidge, duly impressed, said "Tell that to Mr. Coolidge." When the farmer tells the president, he is also duly impressed, but he asks, "With the same hen?" to which the farmer replies, "Oh, no, lots of different hens." Mr Coolidge smiles and says, "Tell that to Mrs. Coolidge."

Remarkably, Coolidge is one of the few presidents whose name is not marred with accusations of adultery.