After a screening of "Robots" last weekend in San Francisco, a boy and a girl slouched against a railing outside the Kabuki theater. They had the air of a couple who had just had an unfortunate date - maybe the waiter had spilled wine on her dress or his credit card had been rejected - except that they were both about 9 years old.

"Robin Williams was kind of funny," he offered.

"Who is Robin Williams?" she asked.

He explained that Williams played Fender in "Robots." Fender is a robot who, despite a desperate need for replacement parts, sustains himself with his big heart and sassy wit. He's the pal of the movie's lead character, a plucky young inventor (and robot) named Rodney Copperbottom (voiced by Ewan McGregor).

"Oh," the girl said. She looked unimpressed.

As well she should be. Williams, who made "Aladdin" a must-see for children and adults alike, feels like an old and not particularly funny joke in "Robots." He does his usual fast-talking shtick, but this time, it doesn't seem worth listening to (nor did it at this year's Oscars or Golden Globes). It's not crisp anymore; it's more of a rambling rant.

His presence contributes to the sense that "Robots," while technologically cool, isn't aimed at children, but rather at the larger humans who hang out with them. The jokes are frequently in bad taste - a homeless robot, sprawled on a sidewalk, holds a sign that says "Got Screwed" - or over kids' heads. In some cases, such as the strange mention of the Brazilian bikini wax technique, that's a good thing. But that a topic best suited to Carrie Bradshaw and her friends is even present in a PG movie indicates how dismal the state of children's cinema really is. The best chance a kid has for a giggle in "Robots" is that old standby, flatulence.

The shame is that the premise of "Robots," in terms of the kind of value system you presumably want your child to have, is quite worthy. Rodney is the offspring, if you will, of a kindly dishwasher (Stanley Tucci) and a housewife (Diane Wiest). It is a blue-collar household, with no room for waste. Love, duct tape and hand-me-down parts keep the Copperbottom family together.

But Rodney takes inspiration from the philosophy of an inventor named Bigweld (Mel Brooks), a cheery populist who also happens to be wildly rich. Bigweld owns the enormous parts factory in distant Robot City, and his motto is that everyone can "shine no matter what you're made of." For a robot like Rodney - who has to wear his cousin's cast-off pink torso, complete with breasts, for his last couple of years in high school - this is inspiration indeed.

He yearns to pull himself up by his bootstraps, which is why he heads for Robot City in hopes of apprenticing with Bigweld. Instead, he is caught in a battle between greedy capitalists and the little "people" who remind him of his father. Bigweld has disappeared and been replaced by a well-buffed crook named Ratchet, who is voiced by Greg Kinnear and looks like that '80s icon Max Headroom. Ratchet is behind the nefarious plot to cease production of replacement parts and force all robots to buy expensive upgrades, thereby sending all the rusty old `bots to the scrap metal heap.

All this has been masterminded by Ratchet's mama, Madame Gasket (voiced by Jim Broadbent), who lives in the fiery bowels of Robot City, melting old 'bots while Tom Waits growls in the background (a scene that caused the little girl next to me to clamber into her father's lap). To make the premise even darker, Madame Gasket is embarrassing to her shiny, square-jawed son; she's really one of the little people herself, but so self-loathing that she wants to wipe out anyone who, like her, isn't smooth and streamlined. These are big, intriguing themes for a kid's movie, and I admire that ambition.

Moreover, the movie, co-directed by Chris Wedge and Carlos Saldanha, who previously teamed up on "Ice Age," has an arresting visual style. The best sequence is a long, mesmerizing journey across Robot City in a robot version of public transit. It's computer-generated showmanship, without much relevance to the story, but it makes the viewer feel like a pinball. In contrast, the worst scene is the climatic battle, which simply mimics stereotypical action movies. Despite everything that I liked about "Robots," I can't get over the feeling that the film is more about what overgrown kids want than what children deserve.

TITLE: "Robots"DIRECTOR: Chris WedgeCAST: Voices of Ewan McGregor, Halle Berry, Greg Kinnear, Mel Brooks, Drew Carey, Robin Williams, Paul GiamattiRATED: PG (some brief language, suggestive humor)GRADE: * * (on a scale of 5)