To say that this is the best American feelgood movie about a lesbian marriage is not to say much, since there is no other one. It would also be to risk a charge of missing the film's point, which it is so ingratiatingly keen to make at every turn: this is not a lesbian marriage, dude; it's just a regular Southern California family in which the kids call their parents Mom and Mom.

That's a fair point, of course. Cholodenko wants you to know that people are just people and its two spouses carry the same load of emotional baggage as anyone in a straight marriage. But the film then goes on to develop a comedy - I mean the term in its Shakespearean sense, as a complicated series of entanglements with an improving moral and a happy ending - which depends entirely on the fact that two of the three main characters are lesbians.

They are Nic (Bening), the obstetrician breadwinner and Jules (Moore), who has done most of the parenting of their kids Joni (Wasikowska) and Laser (Hutcherson), now 18 and 15 respectively and the products of an anonymous sperm donation.The adults are a study in contrasts: Nic's brittle and controlling; Jules is flaky and unsettled. The family muddles along like any other mildly dysfunctional but loving and good-hearted household until the kids decide to track down their biological father.

The law being what it is, that's easily done but when they decide to bring the new guy home to meet the parents, things get problematic. Paul (Ruffalo), is an ubercool organic-food restaurateur who rides a 30-year-old BMW and instantly gets up Nic's nose, not least because he's a college dropout. ("I'm a doer," he explains, and you think she's going to faint).

Through the complications that ensue, it's not hard to see the point that the film is trying to make because it's being made with a hammer, and anyway the title, referencing a Who song, has given us a clue: the kids might be more grown-up than their parents. But, hey, people are just people, right?

It's not exactly a bad film - it's discharged with too much unselfconscious and summery verve for that - but the three adult characters are so irritating and smug you feel like shaking them. It's worth mentioning that almost all American critics have been ecstatic about the film, but down this end of the world, it feels - a bit like Paul - too good to be true.