Is Wanda Maximoff Magneto's daughter?

Question

I've never read the X-Men and Marvel comics, but from watching the films I have come to understand that Wanda Maximoff is the sister of Pietro Maximoff (we see them in Avengers: Age of Ultron).

But Pietro Maximoff is also a character in the X-Men movies, where I can't remember his sister being mentioned.

Part of the plot of X-Men Apocalypse revolves around Pietro and Magneto, but I can't remember his sister being mentioned.

What I would like to know is whether or not Pietro and Wanda are Magneto's children in the comic books, and whether or not they are known to be the children of Magneto in the film adaptations (so, can Magneto be a part of the Avengers timeline, and can Wanda appear also in X-Men movies?)

_{Note: I am not sure where exactly to look for this kind of information, since there are many differing sources online and searching to comic-specific or film-specific resources can be confusing.}

Answer 1

In the comics, Scarlet Witch and her brother Quicksilver were believed to be the children of Magneto for about 40 years, but that history was recently rewritten.

From Wikipedia:

Scarlet Witch is initially depicted as a mutant, born with the ability to alter reality in unspecific ways. Originally introduced as the daughter of the Golden Age superhero Whizzer, a retcon later established she and her twin brother Quicksilver were the children of X-Men villain Magneto. This parentage was their status quo until 2014, when a further retcon revealed that she and Quicksilver were in fact non-mutants who had been kidnapped and experimented on by the High Evolutionary, and then misled to believe that Magneto was their father.

The films are even more complicated, since the rights to Scarlet Witch and Quicksilver (but not Magneto) are shared between Fox and Marvel studios. Fox has the film rights to all mutant characters, but Marvel agreed to not even mention mutants in their films. Since Scarlet Witch and Quicksilver have been core members of the Avengers for many years, Marvel is allowed to use them, but not allowed to call them mutants. Fox included Quicksilver's sister in one scene in X-Men: Days of Future Past, but it's his younger sister, clearly not his twin, so we are left to assume it's his younger sister from the comics, Lorna Dane (Polaris).

So, while Wanda can appear in Fox Studio's X-Men films, so far they haven't included her. Marvel is currently forbidden from using Magneto in their Avengers films, so it's unlikely we'll see them all together any time soon, unless Marvel and Fox strike a deal similar to the one Marvel made with Sony regarding the rights to Spider-Man.

Answer 2

Marvel licensed the filming rights of the X-Men and related concepts, such as mutants, to Fox. Fox created a film series based on the franchise. Years later, Marvel started their own film franchise, the Marvel Cinematic Universe, focused in the characters that they had not licensed to other studios, such as the Avengers. The main core of this franchise were the Avengers, both in standalone films and the successful The Avengers film. Quicksilver and Scarlet Witch were disputed by both studios. Fox would claim the rights over them because they were both mutants and children of Magneto, the villain of most of their films; and Marvel would also claim those rights because the editorial history of the characters in comic books is more associated with the Avengers rather than the X-Men. The studios made an agreement, so that both of them would use the characters. It was made on the condition that the plots do not make reference to the other studio's properties: the Fox films can not mention them as members of the Avengers, and the Marvel films can not mention them as mutants or children of Magneto.

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