Juno *****

Ellen Page as Juno finds she must deal with many things that are, as she says, "beyond my maturity level" when, at 16, she becomes pregnant and decides to have the baby and find the perfect couple to adopt it. Juno is way smarter than her age would suggest, and her observations and reactions to her predicament are quick, cutting, and often hysterically funny. Kudos to writer Diablo Cody (whose account of her life as a stripper marks her as the same kind of free and quirky spirit as Juno) and to director Jason Reitman ("Thank You for Smoking") for this well-observed gem, just the antidote we need for too much Christmas treacle. The movie is, finally, heart-warming, but in its own way, as more than one character grows up a little.

But the highest marks go to Page, who is in turn, and sometimes at once, a kid, a teenager, and a mature young woman. Page is no stranger to acting beyond her maturity level. She was the harrowing star of "Hard Candy," (2006), where she passed for 14 to trap, expose, and punish a suspected child molester played by Patrick Wilson. This movie made less than a million dollars, but is worth renting if you enjoy edgy psychological thrillers. (Guys, be warned, there's a scene of torment that will have you crossing your legs.)

"Juno" seems poised to do well as Fox Searchlight expands the theaters this week to over 900, riding on the wave of its Golden Globe nominations (best comedy or musical, actress, and screenplay). I predict the Oscars will take notice as well, assuming, of course , that there will be Oscars this year. I also predict multiple viewings by groups of girls and young women, who will go back to catch the lines they were laughing too hard to hear the first time.

The rest of the cast is, in a word, superb. Michael Cera ("Superbad") is the sperm-donor boyfriend who gets a chance to realize his maturity level. Jennifer Garner and Jason Bateman are the "perfect" suburban couple (but we all know what kinds of things can lurk in the suburbs). And as Juno's parents, J.K. Simmons (the gruff editor in the "Spiderman" trilogy) and Allison Janney ("Hairspray," "The West Wing" and countless appearances on "Ellen") play the kind of supportive parents a kid like Juno needs.

There is also a stand-out score of independent songs, assembled, I suppose, by Matteo Messina, who was also the composer on "Thank You for Smoking."

Rated PG-13. 92 minutes. Produced and distributed by Fox Searchlight Pictures.