"I presume it's bad enough being hold up at gunpoint when a complete stranger does it. But when your own son does it... o-o-h dear." So says Barbara Richards, towards the end of "The Richards of Streatham", the first of a new run of Relative Values, the programme about unusual families.

Dr Michael O'Donnell narrated, talking to Barbara, her estranged husband Chris and their teenager Scot. But as often with these real-life slices, there was one fact about the participants that was not explored or even mentioned: the fact that they'd agreed to share their story with the world. What good they thought it would do them - Radio 4 doesn't offer tabloid fees or tabloid fame - or anyone listening, was far from obvious. Then you might wonder that about the programme itself.

Briefly: Chris left Barbara when Scot was nine, nobody explained anything to Scot, Scot became extremely difficult, Barbara had him bodily removed to Chris's, Chris was very busy, Scot turned to petty crime, did some drugs, got a gun, held up two newsagents, then went round and pointed it at his mother. He was tried at the Old Bailey at the age of 13, received a two-year sentence, and everyone's now vaguely trying to pick up the pieces. A dire trajectory it was, but not extreme enough to have sensation value, not typical enough to be a cautionary case. What was the benefit in telling it?

Dr O'Donnell, his voice tense with non-judgmentality, tried a little psychology: "Before all this happened, were you a hugging sort of mum?" And he tried a little sociology - for example, about Scot's shirt-thieving period; "We're often told that young people steal to feed their habit. We're less often told the that habit may be for designer labels." Surely, we are told this quite often. But that was about the limit of the programme's reflective range, and by the end we were left with little more than Barbara's own words to repeat: "Oh dear."

Sheer voyeurism? It's better to give it a name more appropriate to an aural medium. Gossip. And like a lot of gossip, it masked itself in a tone of serious concern. Well, nothing wrong with gossip, perhaps, perhaps - when the conditions for gossip exist. It was certainly a story that would get an eager hearing if told about a friend of a friend or a cousin of a partner. But there is something peculiarly nerveless in gossip about people who you don't have any connection with at all.