Jean Grey is a comic book superheroine appearing in books published by Marvel Comics. She has been known under the aliases Marvel Girl and Phoenix, and is best known as one of five original members of the X-Men. As with all cartoon ladies, her female form tends to match the yearnings of teenage boys. I've grown up a little, but Jean is still fun to look at.
Jean, a mutant born with telepathic and telekinetic powers, first saw her powers manifested when her childhood friend was hit by a car. She is a caring, nurturing figure, but she also must deal with being an Omega-level mutant and the physical manifestation of the cosmic Phoenix Force. She faces death several times in the history of the series, first in the classic "Dark Phoenix Saga," but due to her connection with the Phoenix Force, she, as her namesake implies, rises from death.
Phoenix is an important figure in the lives of her husband Cyclops; Professor X, who is like a father and mentor to her; Wolverine who is a very good friend and, at several points, a potential love interest; Storm, who is her best friend and a sister-like figure; her daughter Rachel Summers; her son X-Man; and stepson Cable.
Jean is present for much of the X-Men's history, and she is featured in all three X-Men animated series and several video games. Famke Janssen portrays Jean in the X-Men films.
Thanks to Marvel Comics and Wikipedia.