In current Marvel Universe history, Steven Rogers was a sickly American fine arts student specializing in illustration in the early 1940s before America's entry into World War II. He was disturbed by the rise of the Third Reich enough to attempt to enlist only to be rejected due to his poor constitution. By chance, an Army officer looking for test subjects for a top secret defense research project offered Rogers an alternate way to serve his country. The officer was looking for suitable test subjects for a top secret defense research project, Operation: Rebirth. This project consisted of developing a means to create physically superior soldiers and Rogers was deemed ideal.
Rogers agreed to volunteer for the research and after a rigorous physical and combat training and selection process, was chosen as the first human test subject. He received injections and oral ingestions of a chemical formula that was termed the Super-Soldier Serum, which had been developed by the scientist Dr Emil Erskine (who was code-named "Dr Reinstein"). Rogers was then exposed to a controlled burst of "Vita-Rays" that activated and stabilized the chemicals in his system. Although the process was arduous physically, it successfully altered his physiology from its relative frail form to the maximum of human efficiency, including greatly enhanced musculature and reflexes.
Captain America Vol. 5, #5, together with fellow Invaders Namor and the Human Torch. Art by Steve Epting.Unfortunately, at this moment of triumph, a Nazi spy revealed himself and shot Erskine. Because the scientist had committed the crucial portions of the Super-Soldier formula to memory, it could not be duplicated. Rogers killed the spy in retaliation and vowed to oppose the enemies of America. Meanwhile, the United States government decided to make the most of their one super-soldier and eventually made him a superhero who served both as a counter-intelligence agent and a propaganda symbol to counter Nazi Germany's head of terrorist operations, the Red Skull. To that end, Rogers was given a costume modeled after the American flag, a bulletproof steel shield, a personal sidearm and the name of Captain America. He was also given a cover identity as a clumsy infantry private at Camp LeHigh in Virginia where he made friends with the teenage camp mascot, James Buchanan "Bucky" Barnes.
One night, Barnes accidentally learned of Roger's dual identity and offered to keep the secret if he could become his sidekick. Rogers agreed, and trained Barnes appropriately. Rogers also met President Franklin D. Roosevelt, who presented him with a new shield made from a chance mixture of iron, vibranium and an unknown catalyst. The alloy was indestructible, yet the shield was light enough to use as a discus-like weapon that could be angled to return to him. (In several stories, due to writer error, the shield was described as an adamantium-vibranium alloy.) It proved so effective that the sidearm was dropped. Throughout World War II, Captain America and Bucky fought the Nazi menace both on their own and as members of the superhero team called the All-Winners Squad (in 1940s comics) and the Invaders (beginning with 1970s comics).
Rogers was not the first to be given the Super Soldier formula. It was revealed years later that while Rogers was still being assessed, some military members of the project felt that a non-soldier was not the right candidate and secretly gave Erskine's incomplete formula to Clinton McIntyre instead. However, this made McIntyre violently insane, and he had to be subdued and placed in cold storage. The criminal organization AIM would later revive McIntyre as the homicidal Protocide. (Captain America Annual, 2000).
A beta version of the formula was given to Isaiah Bradley, who became the only survivor of a group of African-American soldiers that "Reinstein" and the military experimented on in 1942. After the last two members of his group were killed, Bradley stole the costume meant for Rogers and wore it on a suicide mission to destroy the Nazi super-soldier effort at a German concentration camp. Bradley was captured, but eventually rescued and court martialed. He was imprisoned for 17 years in Leavenworth until he was pardoned by President Eisenhower. By the time of his release, the long-term effects of the formula turned Bradley into a hulking, sterile giant with the mentality of a 7-year-old. Rogers would not find out about Bradley until decades later (Truth: Red, White and Black, 2003). Patriot, a member of the Young Avengers, has been revealed to be the grandson of Isaiah Bradley, and has inherited his abilities thanks to a blood transfusion.
According to files in the Weapons Plus Program, a clandestine government organization devoted to the creation of superhumans to combat and eventually exterminate mutants, Rogers was "Weapon I", the first generation living weapon. Following his disappearance, the following installments of the Weapon Plus Program moved on to new attempts to create the ultimate weapon, experimenting on animals, racial minorities, criminals and eventually mutants, with results such as Wolverine, Deadpool and Fantomex (New X-Men #145, October 2003).