Science: Male & Female

For hundreds of years, biologists have used the symbols δ for male and φ for female without really knowing—or caring—why. To the incurious among them, the derivation of these symbols might have remained a mystery had not a curious reader of the British magazine New Scientist demanded an explanation. In a recent issue, Dr. William T. Stearn, a botanist at the British Museum (Natural History), tells how the symbols evolved.

Long before biology was born, says Stearn—who borrowed his explanations from a 17th century French scholar—the ancient Greeks gave human qualities to the planets. Mars, the red planet, was considered...