"Baby Mama" isn't exactly laugh-out-loud funny. It's more quiet-chuckle funny, which is fine, too. This latest addition to the pregnancy comedy trend, starring Tina Fey as an overachieving corporate vice president who hires a working-class party girl (Amy Poehler) to be a surrogate mother, ambles along with such low-key, easygoing humor that it's almost a shock to the system: Where are the hamburger phones, the rat-a-tat pop culture references, the porn? All have been left behind in the service of what is a far more observant, if uneven, comedy of 21st-century manners.

A surrogate-pregnancy broker, played by Sigourney Weaver with hilarious superciliousness, puts Kate (Fey) in touch with Angie (Poehler), a hard-edged, slightly ditzy dame who has decided to rent out her womb at the advice of her loser of a common-law husband, Carl (Dax Shepard). When she meets Kate, Angie primly explains that she met Carl "the summer after I discontinued high school," and "Baby Mama" continues in this vein, almost but not quite burying its jokes in the subtle, revealing turn of the phrase.

Kate's boss, Barry, is portrayed by Steve Martin, who, like everyone else in the production, makes the gratifying decision to underplay. Fey and Poehler could easily have become caricatures. Instead, each actress gives her character her dignity, grounding her as a recognizable human being. Even within the contrived confines of its genre, "Baby Mama," which was written and directed by Michael McCullers, rings with a certain degree of truth.

An unforced warmth suffuses the film and makes it such a welcome alternative to the desperation and self-loathing of the Judd Apatow canon or the compulsive verbosity of "Juno." (Which isn't to say that "Baby Mama" doesn't feature its share of raunch: There are plenty of jokes involving sex, childbirth and various lady parts.) For those who crave mannerisms and shtick and like their jokes set up and knocked out with plenty of arrows and quote marks, "Baby Mama" may fall flat. But audiences alive to the modest charms of its take on female friendship will be rewarded with at least a few quiet chuckles.

-- Ann Hornaday (April 25, 2008)

Contains crude and sexual humor, profanity and a drug reference.