Say it ain't so

For a romantic comedy to work-especially one set solely in the land of polka-dot shirtwaist dresses, artsy beachside lofts, and lavishly decorated butter-cream cakes-the premise must be grounded in reality. Though Diane Keaton's latest vehicle, Because I Said So (PG-13 for sexual content), possesses all those pretty ancillary qualities in spades, it is missing the main ingredient.

Keaton returns to familiar territory as Daphne, a pastry chef and single mom to three grown daughters. With her shrieking emotions barely contained by her buttoned-up persona (Something's Gotta Give, anyone?), Daphne involves herself with the love life of her youngest daughter, Milly (Mandy Moore), to the point of voyeurism. She takes out a personal ad on Milly's behalf and then interviews would-be suitors. Of the parade of men who respond, only two are acceptable: Jason (Tom Everett Scott), a successful but uptight architect, and Johnny (Gabriel Macht), a warm single father (one guess which one Milly likes and which one Daphne likes for her).

As a battle over the choice ensues, Milly learns to think for herself, and Daphne learns that life and love can begin anew after 60.

Despite its endorsement of casual sex, Because I Said So embraces a ridiculously retro ethos. We are given no reason why Daphne should worry that "there isn't time left" for her successful, attractive, twenty-something daughter to settle down. And we are offered no explanation as to why a young woman who has built a thriving catering business would be so cowed by her mother in matters of the heart. Most unbelievable: We are supposed to accept that not one, but many men have rejected the likes of Mandy Moore simply because she is a bit clumsy and has a peculiar laugh.

Heaped on top of these implausibilities is a parade of jokes that range from the crude to the banal. In the end, while the mixture looks sweet, it goes down decidedly sour.