To see Ben Elton's "Maybe Baby" is to suffer one of the most embarrassing of things -- a comedian straining to be funny. Successful humour comes out naturally and clearly; it doesn't need to be underlined, shouted or propped up by outlandish gags. There is a scene in this movie where a guy is being read the results of a sperm test, which tell him that a percentage of his little tadpoles are sluggish. "Sluggish?!" he cries. "Couldn't they have figured out a better way of putting it, like 'relaxed'? Relaxed sperm!" When he's told that some are swimming in the wrong direction: "Hello?! They're in a plastic cup!!"

These same lines could be funny, if the guy was desperately muttering them to himself, as rambling thoughts. I can picture Woody Allen playing it like that. But Hugh Laurie, the actor onscreen, shouts and makes expressive gestures, as if playing to a sitcom laughter track. A lot of "Maybe Baby" is like that -- although on the surface the problem seems to be a cheesy screenplay, it's actually the delivery that's off. I kept imagining what the dialogue would sound like if spoken more calmly, and much of it would be witty, warm and funny. That is not a defence of writer-director Elton, but simply an observation. Comedy is a fifty-fifty balancing act of writing and performing, so to screw up even one of these is no small matter.

The story involves a thirtysomething married couple -- happy, well-off, but desperately in want of a child. Sam (Laurie) and Lucy (Joely Richardson) make love morning and night, in time slots carefully planned around Lucy's menstrual cycle, but months go by without any sign of pregnancy. So they begin to try In Vitro Fertilisation treatment; a long, frustrating process that alternately tests their wits and brings them closer together, what with its great need for patience and emotional commitment.

It would be fascinating to see a real movie about the subject of IVF. "Maybe Baby" is not it. We don't get answers to our obvious curiosities, such as whether or not Sam and Lucy get a kid, or how they react to that success or failure. Instead, the plot veers off into Sam writing a screenplay about his marriage, producing it in secret, and then having to heal Lucy's anger when she finds out. Even when Elton is concentrating on the IVF storyline, he seems more interested in the goofy side-characters it gives him a chance to introduce. Among them are a loudmouth Scottish film director (Tom Hollander), a burlesque Australian nurse (Dawn French), and an insane gynaecologist who sadistically dangles his instruments (Rowan Atkinson). None of these people are believable, and since this isn't a slapstick comedy, that means they're not funny.

As I've said, anything perceptive that might have existed in the dialogue is ruined by the over-the-top delivery, so ultimately we're left with nothing interesting but a couple of sexy shots of Joely Richardson. Elton based "Maybe Baby" on his novel "Inconceivable", which he has said was inspired in concept but not content on his own IVF experiences. His reason for not making it more autobiographical was that he felt it would be more personally comfortable to invent contrived humour for the story than use the truth. That's exactly the opposite of how comedians are supposed to work.