Every tick of the biological clock echoes reprovingly in the brain of health food empire vice president Kate Holbrook (Fey).

At 37, she's at the wrong end of the parental age range...and counting. She's also unmarried with no prospects of snaring a willing dad on the horizon.

After drawing a blank with artificial insemination, she's informed by a fertility specialist that she's got a "t-shaped uterus" which leaves her a one-in-a-million-chance of getting pregnant.

Undeterred, she engages the services of Sigourney Weaver's surrogacy centre where - at $100,000 a pop - "it costs more to have someone born than it does to have someone killed"

Despite the six-figure price tag, Kate is offered the dubious services of trailer trash surrogate Angie (Poehler), a blonde good-time girl whose idea of health food is a Big Mac sluiced down with Gatorade.

Director Michael McCullers, who helmed Austin Powers: The Spy Who Shagged Me, cradles similar territory to Judd Apatow's Knocked Up even if he lacks the master's mirth-making touch.

Fey and Poehler are class comedy actresses yet this lacks the dramatic spark which would have been supplied by both their characters genuinely hating the sight of one another.

A bright spot is Steve Martin in his first decent comedy performance in an age as Kate's ponytailed corporate hippy boss who revels in all sorts of nonsensical new age pronouncements.

Ultimately, there's enough to be getting on with and it distinguishes itself from other (baby) formula. Put it this way, it's a lot better than Maybe Baby.

Tim Evans