Kate Holbrook’s (Tina Fey) biological clock is ticking. Problem is, the successful 37-year-old single woman has very little chance of conceiving, and the only way she’s ever going to have a child of her own is if someone else agrees to carry it to term.

Tina Fey and Amy Poehler talk kids in Universal Pictures' Baby Mama

Her prayers are answered in the form of Angie Ostrowiski (Amy Poehler). Not exactly the brightest bulb in the box, she’s healthy, clean and, most important of all, willing to be a surrogate mother for Kate. But when complications arise in the form of obnoxious common law husband (Dax Shepard) and a sexy independent small business owner (Greg Kinnear) the pair’s relationship starts feeling the strain.

But these minor hiccups are nothing compared to the secret whose revelation could very well rip these wildly different women apart destroying any chance at all their arrangement has for success. Yet impending parenthood is a strange thing, and as long as Kate and Angie don’t break down and kill one another the friendship their forming just might have the chance of lasting the rest of their lives.

Baby Mama is the type of good natured adult comedy I want to like more than I actually do. There are some extremely funny moment and some highly agreeable performances, but overall the film moves a bit sluggishly and never catches fire in the ways that it should. While the potential for greatness is definitely here, unfortunately a feeling of safe blandness bordering on the predictable permeates the proceedings, and wile there’s little I can truly rail against here there’s just as few virtues to extol, either.

Pity, because Fey is a winningly eccentric performer who deserves to be a movie star. At times her line readings are so wittily iconic and uproarious (you’ll never look at your Wii avatar the same way again) I almost could have cried they made me laugh so hard. More, She Poehler have electric chemistry honed to near perfection during their stint on “Saturday Night Live,” and as “30 Rock” and Mean Girls have shown the multitalented entertainer is also one of the more exciting and inspiring comedic writers working today.

Problem is, this isn’t her screenplay, it’s writer/director Michael McCullers, and while he admittedly crafts a humdinger of an engaging premise the execution from one of the voices behind the Austin Powers comedies never goes beyond the safe and predictable. He also stretches things out to an almost interminable length, what should be a 90-minute exercise in tightly-wound hilarity instead an almost two hours of sporadically funny obviousness languidly waddling to an all-too familiar conclusion.

There are, it must be said, a couple of aces in the filmmaker’s deck who almost make this thing worth the price of admission virtually on their lonesome. Both Steve Martin (as a pretentious health food store guru) and especially Sigourney Weaver (as the maternal matron of a high-priced surrogate mother agency) are just phenomenal. Every time they make an appearance the film immediately soars to unimagined heights, everything they do such comedy gold I really couldn’t have asked for anything more. 

If only I could say the same for the rest of the film. While nothing stands out as being truly odious or unforgivable that really isn’t saying much. With subject matter so, well, fertile and two female stars ready and willing to do just about anything for a laugh, the fact Baby Mama can’t quite bring it all together is really rather disappointing. For all its strengths and moments of winning inspiration, this is one comedy whose final delivery probably should have been aborted.

Film Rating: êê1/2  (out of 4) 

Additional Links:

-  Baby Mama Theatrical Trailer