To quote the Marvel Fandom Wiki-
May “Mayday” Parker is the first child of Peter and Mary Jane Parker in a future, alternate universe. Peter and Mary Jane were reunited with their baby daughter by Kaine who found the child living with Alison Mongrain, the con-artist who had kidnapped the baby on instruction from the Green Goblin. After they were reunited, Peter lost a leg during a horrific battle with the Green Goblin. After the battle, Peter was offered a bionic replacement from Mr. Fantastic, and considering it a wake-up call, decided to retire and focus on being a husband and father.[5] For years, they chose to keep their past from Mayday and hoped that she wouldn’t develop powers of her own like her father. Despite her parents’ hopes, May began developing versions of her father’s Spider-powers when she was fifteen. At the same time, Normie Osborn (the Green Goblin’s grandson) set out to restore the family name (as he saw it). Mayday donned Ben Reilly’s Spider-Man costume to stop him, but her worried parents burned the costume after May used it to keep her from taking on crime fighting. Days later May was parting ways with her father from the police station when her spider-sense alerted her to a shady character who was stalking her father. She secretly nabbed the stalker, who was intending to kill her father, and beat him up in an alleyway with a trashcan without allowing him to see her identity. This threw the would-be-killer off of Peter’s tail, and May got an addicting rush from saving someone’s life. Over dinner the same night, Peter told his family about the police case he was working on related to a string of murders in the fashion business. May used this info to investigate the fashion store her father was talking about, wondering if the villains behind the fashion murders were the same people trying to get at her dad. While investigating, May wore a makeshift costume from various pieces of black clothing she owned as well as the web-shooters she had saved from Bem Reilly’s costume without her parents knowing. Upon arriving at the store she found a conversation happening between a mysterious villain named Nobody and his henchmen, one of which was the stalker hired to kill her father. While listening in, May was noticed by one of the henchmen, and a battle ensued in which she defeated the goons and Nobody (who used his powers to teleport away when the cops arrived). May rushed home to avoid being caught fighting crime by her parents. However, the escapade had inspired May to use her powers more, and over the next few days she secretly sewed herself a costume and christened herself “Spider-Girl”. Eventually her parents accepted her crime fighting passion and began helping her. May shares traits of both her parents. Like her mother, she is beautiful, charismatic and a popular student. Like her father, she is intelligent and bright. She also inherited his love for in-fight bantering. In addition, she is a very good athlete and excelled in her girls’ basketball team until she quit after her powers emerged. On the other hand, May seems to have inherited the “Parker luck” in which her dual identity wreaks havoc in her private life. May promised to give up costumed super heroics, dated Gene Thompson, and ran for student council president. When Mary Jane became aware that the Hobogoblin posed a threat to her daughter’s teenage friends, she allowed Mayday to resume her activities as Spider-Girl (a situation they wanted to keep secret from Peter). After a battle with the Hobgoblin, May told her father the truth, and after a conversation with Mary Jane, they allowed May to resume her Spider-Girl identity.