Starring Ellen Page, Jennifer Garner, and Michael Cera. Rated 14A. Opens Friday, December 21, at the Fifth Avenue Cinemas and the Cinemark Tinseltown

Hate to break it to you, guys, but Knocked Up wasn't really about the girl. Juno is, however, and a major switch in perspective doesn't blunt the comedy. Initially, the constant stream of one-liners from the mouths of boys and babes too insistently keeps you in laugh land (which does look a lot like Vancouver). But soon after the 16-year-old heroine–named after Zeus's wife–discovers she's pregnant, things keep taking unexpected turns.

Juno MacGuff (Ellen Page) quickly changes her mind after calling the local women's clinic about an abortion, and her approach to keeping the kid–the result of an encounter with her sort-of boyfriend (Superbad's supergood Michael Cera)–is to find "baby-starved wing nuts" in the classifieds. The lucky shoppers turn out to be a well-off couple in the suburbs: she (an impressive Jennifer Garner) is a beautiful, uptight businesswoman, and her husband (Jason Bateman) is a rocker-turned–jingle composer.

Juno gets surprisingly solid support from her gruff dad and dog-loving stepmom (J.K. Simmons and Allison Janney, both terrific), as well as her equally snarky best friend (Olivia Thirlby). Increasingly, though, she is drawn to her adoptive yuppies. The husband's validation of her eccentric taste in music and horror movies is attractive, possibly in a creepy way. But the movie, directed by Thank You for Smoking's Jason Reit ­man from a first-time script by Diablo Cody, keeps your loyalties shifting.

It's this soulful vein of humble emotion that elevates Juno high above most high-school comedies (and adult dramas). It's not hurt by quirky camerawork, deft cutting, a smart soundtrack, and crackling dialogue. Most of all, it has Ellen Page, who graduated from disaster in The Tracey Fragments to again make being an adolescent fascinating, if not easy.