Surely the funniest thing that happened on International Women's Day was Justin Bieber tweeting "Happy International Women's Day...hello ladies ;)", rather late last Friday. Thanks a million, Justin.

Anyway, there isn’t too much competition for the funniest event on International Women’s Day, during which the standards of comedy are traditionally low, so fair play, Justin.

Justin seems a careful kind of lad and he tries hard to cover the waterfront. In giving a cyber salutation to the ladies Justin was aiming not, of course, at his fans, but at their mothers. While collecting an MTV award in Los Angeles in 2011 he gave thanks “Not only to God but to Jesus”. Well, I think that’s everybody. It’s sad to see a teenager so cautious in these matters. And so rash in others. Justin Bieber had a rough time last week during which he played several dates at the O2 in London. Turned up late on Monday. Passed out backstage on Thursday. Whacked a photographer, or threatened to, on Friday. You know yourself.

Ever since some fool was stupid enough to open the back doors of the Bay City Rollers' tour van we, the female public, have been coming to terms with the reality of our teen idols. And I'm sorry to say that it's never pretty although the boys almost always are. David, Donny, Marc, Michael, Take That, Boyzone, Justin Timberlake, Zac Ephron back when he sang — Justin Bieber could be their brother in the peachy adolescent acceptability they embodied all those years ago. The young, skinny and essentially harmless-looking Frank Sinatra was one of the very first teen idols. Adolescent girls were doing metrosexual generations before the term was coined.

From the time that pop ate itself – several decades ago now – the career of the teen idol has been the toughest. Teen idols only earn respect if they manage to survive and continue working into their twenties. Not many of them make it that far.

No matter how young they start – and Bieber has been performing since he was 13 – the teen idol is the oldest figure in pop. Justin may have 35 million Twitter followers and accrue new ones at the rate of 21,000 every 15 minutes. He may have broken into show business through marketing on social media and appearances on YouTube, allegedly posted by his mother, Pattie. But at bottom he is an old-fashioned boy; that's what he's paid for. Justin Bieber has sold 15 million records and has a quiet talent for making sound investments in Silicon Valley. The Bay City Rollers never had it that good.

Teen idols
Teen idols, like so much of the music industry, are paid with female money; or at least with the money of the female's parents, which is almost the same thing. Whilst the performers have not really changed in 50 years – a haircut here, a jacket there – the mothers most certainly have. Louise Cooper is a financial analyst who brought her 9-year-old daughter to the O2 concert in London last Monday when Justin Bieber was lowered on to the stage two hours late. She told Associated Press: "It is one thing if your demographic is 50 year olds but his demographic is lots of little girls who need to go home and go to bed."

This is not the kind of language that was heard at Take That concerts – at least not until they did the reunion tour.

But despite the punctuality difficulties which annoyed so many parents at the London concert last Monday – which was, after all, a school night – in most respects Beliebers (his fans) get good value. A couple of token tatoos cannot take from the fact that Justin, now 19 – his birthday is on March 1st – is so cute that he looks like a toy and irredeemably wholesome. It’s just that it is undeniable to anyone with a knowledge of pop history – that is, to anyone who can remember as far back as The Pussycat Dolls – that he is trembling on the cusp of teen idol disaster, which is coming for him just as surely as night follows day.

The teen idol has always been a children's entertainer. As he or she emerges into adulthood the strain of pretending to be a child oneself is bound to start causing problems, just as surely as the children's party conjurer eventually hits the gin.As Bieber was photographed in his hospital bed last week – bare chested – the middle aged of several continents could see the classic shape of a teen idol burn-out emerging from the ether. Again. We started humming "Tradition" from Fiddler on the Roof as the spooky thunder rolled.

Squeaky clean
Meanwhile David Bowie ( 66, birthday January 8th ), far from being a rock and roll suicide, or The Thin White Duke, has become some sort of rock and roll saint, and goes to the gym. David Bowie, that cross dressing, eyebrow-plucking, drug-taking mess – this is not a criticism, I loved him like a brother – is now squeaky clean and, where once he was reviled as a threat to masculinity everywhere, gets universal male approval. All the men in the media think that David Bowie is deadly. All the men in the media think Justin Bieber stinks. All the little girls are ready to move on to another boy singer.