I feel like I should be unabashedly in critic love with Ellen Page, but I’m worried about her. She’s been wonderful in a couple films, but I fear that without some serious development she may burn through her bag of tricks even before she can have a 20-something flameout. It’s one thing to be preternaturally self-aware at 15, and quite another at 25. To keep up her current pace, she’ll have to take on Patti Smith and Eleanor Roosevelt within the next eighteen months, then retire.

In the meantime, she expertly carries Juno, guaranteed to be the Little Miss Sunshine or Knocked Up of whatever season Fox Searchlight deems safe to deliver it into wide release. (It opens limited on Dec 21 to qualify for Oscar.)

After a single sexual experience with ‘not really a boyfriend’ Paulie Bleeker (Michael Cera) leaves her pregnant, 15-year old Juno McGuff (Page) decides to carry the baby to term. She hopes to donate the child to a couple unable to conceive, and finds a seemingly perfect couple thanks to an ad in the Penny Saver. Mark and Vanessa Loring (Jason Bateman and Jennifer Garner) seem cute enough for Hallmark, so Juno makes a deal to give them her newborn.

Jason Reitman’s follow-up to Thank You For Smoking is, to my mind, more balanced and on pitch than Knocked Up. Scripted by blogger/memoirist Diablo Cody (author of Candy Girl: A Year In The Life Of An Unlikely Stripper) with an ear for barbed observation and an avoidance of easy stereotypes, this isn’t exactly an after-school special against teen pregnancy. (Even so, the story wraps up far too tidily, and as much as I enjoyed the film, I walked away feeling more manipulated than I’d like.)

Juno navigates tricky waters with nearly everyone in her life. She reveals the pregnancy to father and stepmom (J.K Simmons and the thoroughly wonderful Allison Janney) and finds them surprisingly supportive. Shy would-be boyfriend Bleeker is less obviously useful, but would probably be there for her if she asked. Her friend Leah (Olivia Thrilby), at least is unquestionably on her side.

A trickier prospect than most is Mark, the adoptive father who isn’t quite ready to leave his ’20s. Mark digs cool music and makes mixtapes for Juno. He isn’t addicted to Pottery Barn and baby room color patterns, unlike his wife. Cody and Reitman dash headlong to the edge of a frightening precipice with Mark and Juno’s friendship, but skid to a stop before taking the deadly plunge.

Diablo Cody’s dialogue is always funny, but frequently comes across as wish-fulfillment in the sense that she’s too eager to put the sharp humor of a very experienced 20-something into a teenager’s mouth. This puts real demands on Page’s skills and asks her to tread a thin line. Frequently she manages to spin too-worldly dialogue into the sort of stuff a kid might spout in hopes of sounding confident and mature. As Page plays it, Juno may often be right, but she doesn’t always know it.

Page has to be good, because she’s up against a universally great cast. This is my favorite J.K. Simmons performance in some time; he feels supremely natural and warm without sacrificing authority. The ‘behind the scenes’ dialogue between him and Janney, who elevates the thankless stepmother role into the stratosphere, is perfect. As is Jennifer Garner’s too-eager desire for motherhood. Michael Cera is rather minimized, and you’ll want more of The Office‘s Rainn Wilson after he appears in one scene.

Unfortunately, Juno also has the distinction of making me wish for the eradication of all cute songs about relationships and coming of age. At the very least, I’d sacrifice the Garden State soundtrack, since it provides exactly the wrong role model for a movie like this. Any time Reitman gathers steam, he downshifts into a cutesy segue, complete with ‘quirky’ hand-drawn titles and candy-like indie rock songs so sweet they leave a soft rain of powdered sugar every time a beat drops. They’re overt McSweeney‘s moments. They’re porn for Sarah Vowell. Spontaneous diabetes sucks, and I got it a couple times during this film.

For every saccharine misstep there are half a dozen lovely incidents. Days later, I can still get a giggle out of Juno’s interaction with a fellow student picketing an abortion clinic, the way Allison Janney berates Juno’s ultrasound technician, or the very awkward meetings between Juno, her father and the Loring family. I’ll give a hall pass to one cute song incident, which I won’t spoil, since it’s part of the conclusion. It’s the one that feels right.

I’m being so hard on the use of music because it feel forced and self-consciously sweet, when the rest of the film is so genuinely charming. It feels effortless, effervescent. Juno, with all it’s painful and awkward events, generated the biggest and most plentiful smiles of TIFF ’07; I just loved watching this movie.

8.8 out of 10