Robert Bruce Banner was the son of Dr. Brian Banner, an atomic physicist, and his wife, Rebecca. Brian became convinced that his work in radiation had altered his own genes, resulting in what he saw as a hated mutant offspring. Brian Banner drove himself insane with these fears and murdered Rebecca while trying to kill Bruce. Brian was shot by police before he could harm his son.
Bruce graduated high school and studied nuclear physics in Navapo, New Mexico, at Desert State University. With mutants exploding onto the worldwide scene, and the belief that radiation might be the cause of this epidemic, Bruce was invited to work for the United States Defense Department at the nuclear research facility at Desert Base, New Mexico. Bruce's main goal was to create a way for the United States to manufacture its own super-army. Banner went to work immediately, but met with little success.
With General "Thunderbolt" Ross constantly breathing down his neck for results, Bruce took some shortcuts in his research. These shortcuts ended with disastrous consequences. During the preparation for one of his new Gamma Radiation tests, Bruce was dosed with a lethal amount of Gamma rays. These rays, however, did not kill him. Instead, Bruce was transformed into a huge monster. He rampaged across Desert Base and destroyed it completely.
Believing the attack to be mutant in nature, Ross ignored his superiors' orders and pursued the monster that would become known as the Hulk with the remaining men of Desert Base for close to a month. As the Hulk, Bruce eventually destroyed Ross' army in San Diego, CA. Following the battle, the Hulk fled into the ocean.
Bruce awoke days later in Australia in the care of Aboriginal people who had taken him in. Bruce vaguely remembered his time as the Hulk. At one point, Magneto himself, assuming the Hulk to be a mutant, visited Banner and offered him a chance to join him in his fight against the humans. Banner declined and asked to be left alone. Magneto reluctantly agreed. Banner is happy to remain out of the public eye and fears what would happen if the Hulk was ever released onto the world again.