Mayday Parker inherited the fantastic powers of her father, Peter Parker (better known as spider-like abilities that Peter Parker received as a teenager following a radioactive spider bite. Fascinatingly, an issue of The Amazing Spider-Man addresses this question directly.
In the mainstream Marvel universe, Peter Parker and Mary Jane Watson’s daughter was killed by the Green Goblin, in one of the most disturbing psychological attacks on his nemesis. In the alternate MC2 Marvel continuity (Earth-982), Mayday survives and eventually develops superpowers as a teenager. As Spider-Girl, Mayday takes Peter Parker’s place following his retirement from his superhero career (following a grievous injury), but the fact that she’s born with her abilities would understandably make one wonder if she’s a mutant or a type of mutate like her father.
The mainstream Marvel universe answers this question in issue 415 of The Amazing Spider-Man, by Tom DeFalco and Mark Bagley. As Ben Reilly and Peter Parker battle a gargantuan, mutant-hunting Sentinel robot, it detects an anomaly in Mary Jane Watson, who is pregnant with Mayday. While the Sentinel notes that the embryo is not that of a normal human, it doesn’t declare it a mutant and therefore doesn’t attack Mary Jane.
Numerous beings in the Marvel Comics universe are born with superpowers, and, unsurprisingly, not all share the same origin for their abilities. What separates mutants from other human-like beings who are born with superhuman abilities is a specific gene called the “X-gene.” While mutant powers vary greatly from person to person, the X-gene is one of the few consistent traits, and it’s likely what the Sentinel in The Amazing Spider-Man was scanning for when detecting the anomaly in Mary Jane.
So, Spider-Girl is born with her superpowers but she lacks the X-gene, putting her in a gray area where she isn’t a human but not a typical mutant either. Marvel editor Tom Brevoort addressed this question from a fan on social media as well, further confirming that, while not an ordinary human, Mayday is not a mutant either. The best way to describe Spider-Girl is that she’s a mutate, whose powers come from her father, Spider-Man, rather than the mutant X-gene.
