Henry "Hank" McCoy was born and raised in Dunfee, Illinois, the son of Norton and Edna McCoy. His father worked at a nuclear power plant where he was exposed to massive amounts of radiation during an accident. Norton was completely unharmed, but the radiation affected his genes and, as a result, his son was born a mutant. Unlike most mutants, Henry showed signs of mutation from birth: unusually large hands and feet. A prodigy, Hank was also endowed with an innate superhuman intellect and during adolescence he gained the power of simian-like augmented agility, reflexes, and strength.