Many women have been known as Marvel Girl. The first was Jean Grey. As a founding member of the X-Men, Jean has been fighting for the peaceful coexistence of mutants and humans most of her life. While piloting a spacecraft back to Earth, Jean was saved by the Phoenix Force and placed in a cocoon to heal, while the Phoenix impersonated her. After returning, Jean joined the founding members of X-Men in X-Factor and later rejoined the X-Men. Later, Rachel Summers, the mutant daughter of Cyclops and Jean Grey of another timeline, was rescued by Storm's X-Treme X-Men and returned to the X-Men, where she learned that Cyclops was having an affair with former villain Emma Frost, and changed her name to "Rachel Grey" and her codename to Marvel Girl, after Jean was killed by Xorn. After learning of Cyclops' long-lost brother, Gabriel Summers, Rachel went into Shi'ar space and joined the Starjammers, but, upon returning to Earth, Rachel learned that Cyclops had moved the majority of the mutant population to Utopia. After Cyclops had a fight with Wolverine, Wolverine left to rebuild and reopen Xavier's School for Gifted Youngsters, as the "Jean Grey School for Higher Learning", and Rachel returned to Westchester.