In theaters

BABY MAMA written and directed by Michael McCullers, 96 minutes, rated PG-13.

The new Michael McCullers movie, “Baby Mama,” goes down like a tall bottle of warm Similac. And that’s a good thing.

Based on McCullers’ script and set in Philadelphia, the film stars Tina Fey as Kate Holbrook, a successful 37-year-old business woman who is living the high life, albeit with a bum womb.

Apparently, her womb is T-shaped, which pretty much spells trouble since single Kate is finding it impossible to get pregnant in spite of repeated efforts at artificial insemination.

At the start of the movie, her doctor tells her she has a “one in a million chance” of conceiving, so Kate does what any resourceful individual would do – she decides to look into adoption agencies, which curiously won’t have anything to do with her, and then she chooses another route, one that ultimately changes her life.

She goes to an agency that specializes in connecting people like her to surrogate mothers like Angie (Amy Poehler). The agency is run by the unusually fertile Chaffee Bicknell (Sigourney Weaver, very funny in a role that finds her smiling gracefully through an onslaught of old-age jokes), who apparently can get pregnant at the drop of a wink. What Chaffee devises for these two women will mean tens of thousands of dollars to Angie, the same to Chaffee, and a child for Kate, who wants a baby more than anything.

But at what cost? For Kate, it turns out to be higher than expected, particularly since Angie isn’t exactly the cultured woman Chaffee promised. Instead, she’s a crude, combative mess, the sort of person not above relieving herself in the bathroom sink if the toilet happens to be unavailable.

When Angie decides to dump her common-law husband, Carl (Dax Shepard), she moves in with Kate, which allows the two to bond, argue, go to nightclubs and enjoy bouts of karaoke even while a major twist brims on the periphery.

Though the movie never reaches its full comedic potential – it’s too nice and too safe to really dig in and go for the bigger, rowdier laughs – it’s still fun. A good deal of this is because of the chemistry shared between Fey and Poehler, whose years of working together on “Saturday Night Live” allowed them to perfect their shtick to the point that it eclipses the movie’s shortcomings (specifically, its shoddy direction).

Lifting the movie higher is Steve Martin as Kate’s boss, a pony tailed phony who has made millions in the whole foods movement; the actor hasn’t been this loose in years, likely because the film’s success doesn’t fully rest on him. Greg Kinnear is stuck with the least-interesting role as Kate’s dull love interest and he fares less well, though Romany Malco as Kate’s doorman does have a go of it in a part that could have been equally as forgettable. Here, it isn’t. His best scenes are shared opposite Poehler, the film’s true star, whose manic energy and cagey reactions go a long way in making this “Baby” work as well as it does.

Grade: B

On DVD and Blu-ray disc

THE GOLDEN COMPASS written and directed by Chris Weitz, based on the novels by Philip Pullman, 114 minutes, rated PG-13.

Chris Weitz’s “The Golden Compass” is undeniably a great-looking movie. A very good Nicole Kidman, for instance, is a golden vision of cinematic perfection, slinking with menace through an otherwise imperfect film stymied by a dense script and a chafe, baited ending that offers more disappointment than satisfaction.

Weitz based his script on the first book in Philip Pullman’s “His Dark Materials” trilogy, and he used his $180 million budget to create a world that hovers somewhere between the sterility of science fiction and the richness of fantasy. As a result, the movie can be beautiful and harrowing, but too often, also canned and derivative.

In many ways, “Compass” will remind viewers of 2005’s “The Chronicles of Narnia: The Lion, The Witch and The Wardrobe,” a superior film that grabbed audiences from the start with its well-rounded characters and the seamless incorporation of its special effects, which were among that year’s best.

Though “Compass” follows “Narnia” in that it created something of a stir within the restless Catholic League, which condemned the movie for what it views as atheist undertones, it otherwise is nowhere on par with “Narnia.”

What’s missing isn’t just a sense of magic to the production and a clear idea of all the evil working to undo young Lyra (Dakota Blue Richards), who is in possession of the golden compass of the title, an alethiometer used to mine the truth in all things asked of it. What’s critically missing is soul, momentum and a lasting element of danger, all of which would have helped “Compass” match “Narnia’s” operatic tone.

About the compass of the title: Lyra receives it from her uncle, Lord Asriel (Daniel Craig, wasted), who instructs her to keep it hidden from Kidman’s Mrs. Coulter, a glam tour-de-force who represents the Magisterium (or the Catholic Church – you decide), and who is all about crushing free will in children.

Helping Lyra fight Coulter and the Magisterium is the warrior polar bear Iorek Byrnison (Ian McKellen) – whose battle with Ragnar (Ian McShane) allows the movie its much-needed slice of action – as well as the Gyptians, scores of witches and even Sam Elliott as a gun-toting cowboy. And there’s more – too much more, really – with the movie eventually collapsing beneath the weight of all its unanswered questions.

Grade: C+

WeekinRewind.com is the site for Bangor Daily News film critic Christopher Smith’s blog, video podcasts, iTunes portal and archive of hundreds of movie reviews. Smith’s reviews appear Mondays, Fridays and weekends in Lifestyle, as well as on bangordailynews.com. He may be reached at Christopher@weekinrewind.com.