Avengers: Endgame left audiences with multiple threads to tangle, not the least of which were the ramifications of Steve Rogers' decision to remain in the past with Peggy Carter. The film's writers, Stephen McFeely and Christopher Markus, recently confirmed that Steve is not only the husband referenced in 2014's Captain America: The Winter Soldier, but also the father of Peggy's two children. "It does introduce the idea that there are two children who have somewhat Super-Soldier DNA," Markus said.
But Endgame isn't the first to raise the possibility of Captain America's superheroic offspring. Steve Rogers fathered two children, each of whom inherited his Super-Soldier DNA, in animation and in comics, at least in alternate realities. However, Peggy Carter wasn't their mother.
James Rogers
James Rogers was introduced in the 2008 animated film Next Avengers: Heroes of Tomorrow, in which the children of the Avengers take up the mantles of Earth's Mightiest Heroes after their parents fall in a battle against Ultron. Raised in safety with the other children by Tony Stark, James becomes the leader of the new generation of Avengers, and poses arguably the greatest threat to Ultron. He has all of Captain America's abilities as well as an energy shield created by Tony Stark (the original Vibranium shield is in Ultron's possession).
James helps to turn the tide against Ultron, defeating the foes his father couldn't. He also ends up fighting robot duplicates of his own parents, Captain America and Black Widow. Yes, in this continuity, Steve Rogers marries Black Widow, and the two have a son.
James, or at least a version of him, was introduced to Marvel comics along with the other Next Avengers in 2011, in S.H.I.E.L.D. #4.
Sarah Rogers
Sarah Rogers, on the other hand, is a little more unusual. James Rogers is very much what someone would expect of the child of Captain America: a determined leader who follows in his father's footsteps. But Sarah is a little more unusual.
Introduced in 1998 in What-If Vol 2 #114, Sarah exists in a universe in which the Avengers left for Battleworld in the classic Secret Wars crossover, but never returned. Instead, they founded a colony there and began a new civilization. Sarah is the child of Steve Rogers and the X-Man Rogue.
The idea of Rogue being able to conceive any child due to her mutant ability makes this relationship already more than a little bizarre. Stranger still is how, in this alternate continuity, everyone refers to Rogue as "Carol." Considering this event takes place after Rogue drained Carol Danvers' essence, placing the then-Ms. Marvel into a catatonic state, it's implied that Sarah's mother is actually Carol Danvers inhabiting the body of Rogue. Maybe? The implication is that Carol Danvers, in Rogue's body, learned how to control Rogue's mutant abilities, and, thus, could conceive a child.
As such, Sarah possesses all of the abilities of Rogue after she absorbed Ms. Marvel's essence, making her incredibly powerful. In the story, she has to travel back to Earth to stop the son of Doctor Doom from taking over reality. Along the way, she acquires Thor's enchanted hammer Mjolnir for good measure, proving she's not only suited to follow in her father's footsteps, not only possesses the powers of both Rogue and Carol Danvers, but is also worthy of the power of Marvel's god of thunder.
She arrives on Earth, using the powers of Mjolnir and a device constructed by the Hulk, to link Battleworld and home, only to find the world swarming with Sentinels. But, naturally, she decides to stay on Earth and lead a new group of teenage heroes to ward off the robotic overlords. As you do.
Directed by Joe and Anthony Russo, Avengers: Endgame stars Robert Downey Jr. as Iron Man, Chris Evans as Captain America, Mark Ruffalo as Bruce Banner, Chris Hemsworth as Thor, Scarlett Johansson as Black Widow, Jeremy Renner as Hawkeye, Brie Larson as Captain Marvel, Paul Rudd as Ant-Man, Don Cheadle as War Machine, Karen Gillan as Nebula, Danai Gurira as Okoye and Bradley Cooper as Rocket, with Gwyneth Paltrow Pepper Potts, Jon Favreau as Happy Hogan, Benedict Wong as Wong, Tessa Thompson as Valkyrie and Josh Brolin as Thanos. The film is in theaters now.