Libby Gruner writes a column for Literary Mama called Children's Lit Book Group. Her most recent article, Vampire Love, is about the Twilight series.
In it, Gruner says, "Vampire stories are, of course, perfect for teenagers. Vampires stay out all night, scare the respectable citizens, take crazy risks, and live, seemingly, forever. And they're both sexy and dangerous. Their feasting is intimate, and it's transformative: the first time matters."
Gruner also suggests that Edward is a parody of the stereotypical 50s girlfriend with his insistance on "waiting for marriage" before "turning" Bella. (The wedding night will involve both first sex and murder in Edward and Bella's case. Analyze that.) She feels that "Meyer's novels seem anxious about modern life," which I can also agree with.