Carol Sarler: The dressing-up box is a pretty safe place for little girls to play

When David Cameron declared his stern intention to hammer the heads of any and all advertisers engaged in what he calls the "sexualisation of children", he must have known from get-go that he couldn't put a foot wrong. He knew, for instance, that the broadcasters would supply disproportionately large coverage to his rather vague threat; it's not every day, after all, that they have the chance to pepper their early evening bulletins with such pretty little brassieres – suitably accompanied by censorious voice-overs, just in case anybody might suspect them of enjoying themselves.

He knew, too, that his views would be met with almost impenetrable consensus, at least among the population old enough to vote; he knew because his targets have taken similar batterings countless times in the past few years, and although on each occasion nothing much of any meaningful effect has been done, none the less the outcry has been consistently musical to a political ear.

Boycotts and bans have been urged against retailers for selling T-shirts bearing Playboy bunnies and slogans such as "I love boys – they're stupid"; Tesco had its collar felt by public opinion for flogging weeny toy pole-dancing kits, while Next and even high-street stalwart BHS came under the cosh for lingerie deemed unsuitable for prepubescence.

Music and entertainment have also traditionally taken their share of the blame. Mr Cameron's personal reluctance to allow his six-year-old daughter Nancy to listen to Lily Allen, while wholly understandable on the grounds of artistic merit, only echoes the condemnation for Britney Spears's "flaunting" of herself dressed as a schoolgirl – even though she was 17 at the time, so at a stretch could actually have been one – and who among us can forget the horror of middle-class mothers when small girls patted their cutely unformed bottoms in time to "The Cheeky Song (Touch My Bum)"?

Lack of originality does not, of course, diminish Mr Cameron's sincerity. Votes aside, he probably does wish, most fervently, to banish all such corrosive influences. Even if his own language on the subject veers to the purple – the "taking away of innocence" that is "so precious" – this is only because fathers of girls are fiercer than anyone on these issues.

Within this sincerity, however, lies the rub: he does not exactly mean what he is saying – any more than, as the examples above demonstrate, any previous fellow agitator exactly meant it either. What they say is that they seek to vanquish the sexualisation of little children; what they mean is the sexualisation of little girls. And the difference matters.

All children, when small sprouts, hold in common a fascination with the adult world. No wonder: it is alarming and tantalising in equal doses, uncharted, unknown, vaguely glamorous, replete with adventure and as devilishly unknown as it is their inevitable, inescapable future.

To make controllable sense of it, they play with it: they play Mummies and Daddies and Doctors and Nurses; they are spies or soldiers or heroes or daredevils or witches or shopkeepers or movie stars or Simon Cowells (yes, really). As part of the process of play, they ape it; they adopt, say, the language or inflection of a soap opera and given half a chance they seize a costume for their drama.

Most women, and a great many men, treasure memories of descending a staircase all grown up in a mother's frock, its hem trailing behind like a wedding train, face skewed by lopsided lipstick. Heaven! In our family we were especially blessed – and certainly our friends thought so – because having parents with a yen for amateur dramatics meant a huge, three-tier make-up box stuffed to its gills with theatrical gloop. By the same token, most men, and a great many women, still recall the childhood feel of the plasticky gun or the bows and arrows with which we could slay Injuns or Nazis or, on a good day, both.

Since then, make-believe has given way to making money. Commerce stepped in, together with its ferocious advertising wing, and whether we like it or not – much like David Cameron, I must say that I do not – the natural, imaginative curiosity of children has been harnessed for exploitation. So be it. If you resent it enough, go and bring about the downfall of capitalism, why don't you.

Thus: toy guns are now expensive replicas of discomfiting accuracy in order that a boy might, to his own eyes at least, better look like a man; toy brassieres – and toys they surely are – are now replicas in such copycat detail that a girl might, to her own eyes at least, better look like a woman. Sad, certainly. But when a small boy shows off to his friends the costly gun that he or his parents have been coerced into buying, nobody thinks that he is rehearsing or preparing to kill somebody. Equally, when a small girl shows off her silly lingerie, she is neither rehearsing nor preparing for real sexual activity; in their own minds, both of them are simply playing at grown-ups. Yet if the boys' and the girls' reaction to their toys is the same, ours is not. And perhaps it should be.

If we can accept that a boy with a pretend gun will not become so conditioned that he automatically grows up to a be a real gun-totin' cowboy, why can we not as easily accept that a girl with a pretend bustier is just as unlikely to grow up to be a real vamp? If politicians do not build campaigns upon the brutalisation of boys, why is the sexualisation of girls fairer political game?

I don't deny that you and I might see a difference between the two purchases; that the absence of flesh inside a functionless bra cup, for instance, serves to heighten awareness of the breast that will one day come along to fill the space. But it does not matter what you and I see; what matters is the perception of the girl wearing it. And just as I attached no overt sexual connotation to the newspaper I shoved into Mum's bra cup when I "borrowed" it, or to the purloined eye shadow, or to the teetering high heels, I am prepared to trust that the nine-year-old girl today reserves the same healthy disdain for the act of, eeeuw, sex that nine-year-olds always have.

In other words, she is not "sexualised" in her eyes; only in ours. Until, that is, we pass it on to her, which is something that "we" – to use the term loosely – do to girls all the time. In a woefully misplaced parody of protection, a girl is constantly warned against risking the attentions of a paedophile – fair enough, as girls are far more at risk than boys – but every time we do it we are also telling her, whether she needs to know it or not, that she is sexually tempting. Ergo: sexual.

We battle the advertisers by trying to dissuade the purchase of the toy dance pole or the saucy T-shirt – which, left to themselves, would probably have all the lasting appeal of the Cheeky Girls – because, we say, she'll look like a slut. A what? Oh, I see. Very sexual.

We quote self-appointed experts, who swear that a child's Playboy bunny T-shirt is not just a picture of a rabbit in a dickie but a harbinger of everything from low self-esteem to anorexia – with no supporting evidence – and once again the little girl, listening in, hears herself described in sexual terms.

Now we run election campaigns by introducing more of the same: look at that television, little girl, see the tea-time news! There's that nice Mr Cameron, saying that you are "sexualised".

But the obsession with sex is ours; it is the suspiciously seedy product of adult minds. A cynic might even suggest that our noisy disapproval actually permits us to revel in it further, to bask in titillation from the safe grandstand of the higher moral ground.

But the greater good could probably be served, at least to our daughters, by revelling rather less; by down-grading sex from relentless political attention, dubious psychological analysis and prurient debate in favour of the light-hearted family joke, the brusque dismissal of the please-Mum (nine-year-old girls don't buy their own lingerie), the waiting-out of passing fashion and the offering of a distraction of greater interest. A huge, three-tier make-up box, perhaps, stuffed with theatrical gloop?