Alexander Summers is the son of Major Christopher Summers, a test pilot for the U.S. Air Force, and his wife Katherine Ann Summers. He has two brothers, older brother Scott Summers and younger brother Gabriel Summers. All three of whom are mutants.
When Scott and Alex were boys flying home from a family vacation in their father's vintage private plane, a scout ship from the alien Shi'ar Empire suddenly materialized and set the plane ablaze. Katherine pushed Scott and Alex out the plane door with the only available parachute. The parachute caught fire, so Scott used his mutant optic blasts for the first time to slow their descent. Scott and Alex were unaware that their parents had been teleported from the plane by the Shi'ar a moment before it exploded. Scott suffered a head injury on landing that damaged the part of Scott's brain that would have enabled him to control his optic blasts. The two boys were hospitalized and both suffered traumatic amnesia regarding the incident.
They left the hospital after two weeks and were placed in the State Home for Foundlings, an orphanage in Omaha, Nebraska and were subjected to a battery of tests and experiments by the orphanage's owner, Mr. Milbury, an alias for the evil geneticist and their future enemy Mr. Sinister. Sinister believed that Scott was the Summers brother with the most potential, so he had Alex adopted to separate them and render Scott emotionally vulnerable.
