THERE was a sense of déjà vu around the fuss over Jennifer Lopez's recent appearance on Britain's Got Talent, wearing a black PVC leotard and thigh-high leather boots, performing dance moves that owed a little too much to the culture of lap and pole-dancing.

A small wave of Ofcom complaints followed – and became the excuse for newspapers and websites to publish titillating stills of J-Lo in various raunchy positions that made her dance seem still more pornographic. Alongside them, they published choice objections that had been posted on Twitter, such as: "Put some clothes on, it's a family show."

On parenting website Mumsnet, people complained that kids were watching the show; that kids were performing on it. There were echoes of anxieties voiced earlier in the series when Asanda Jezile, 11, performed a Rihanna song, aping some of the singer's sexy moves. This sparked a chorus of Twitter angst which saw her as "clear proof Rihanna is no role model".

Of course, we have been here before. A couple of years ago it was Rihanna on The X Factor, whipping off her robe and jiggling in a bikini. Before that, it was Christina Aguilera on the same programme, performing her song from the movie Burlesque, which involved grindings and gyratings and hooker/show-girl costumes. Both these performances appeared before the 9pm watershed, and, following complaints, Ofcom issued new guidelines. Britain's Got Talent was not breaking these guidelines – J-Lo's performance was scheduled 40 minutes after the 9pm watershed. But still parents felt in some way betrayed.

Cue another chance for people to air their discomfort with the so-called "pornification" of our culture, or the "hyper-sexualisation" of young girls. This is one of the recurrent anxieties of our time. It's hard to be a parent and not share it – even I, the mother of sons, not daughters, feel it. We don't indulge in the family ritual of watching Britain's Got Talent, so I didn't get the chance to hover over the remote control, wondering whether I did or didn't want to put a halt on J-Lo. But I know what it's like to casually pull up my six-year-old son's latest favourite song, Taio Cruz's Dynamite, on YouTube, and then slap the laptop screen down after finding the video features a bevvy of scantily-clad ladies lounging over automobiles, prancing in foam and jiggling ecstatically around him.

To many, the gyrations of J-Lo will seem minor by comparison with the world of dark secrets contained on the internet. Why fuss over a bit of grinding on telly, when there are bigger fish to fry? Shouldn't we be more concerned by issues like campaigning for a block on online child abuse images in the wake of the convictions of Mark Bridger and Stuart Hazell, both of whom had been users of extreme material? And as Icelandic campaigners battle to make their country the first to ban violent or degrading internet porn, shouldn't we be considering following in their wake?

Except that what happens in the mainstream, what appears to be sanctioned by our society, does matter. What bothers me most for my children are the images we find openly everywhere: on television, in supermarkets, in newspapers. These worlds seem official in a way the hidden, mostly untalked-about, but readily accessible underworld of internet porn is not. They are what really shape us. Britain's Got Talent occupies a prime spot in that very official mainstream. A friend recently told me she sometimes worried she was making her children into outsiders because they did not, like everyone else, watch the show. Boycott it, and we are not participating in our shared culture.

I am not particularly fearful that my children encounter images of sex at this early age. What troubles me about this process so often described as pornification, rather, is that it has nothing to do with the actualities of sex. What children are learning, and what we are having thrust in our faces through these shows and videos, isn't the intimate sexual act, but the use of moves and poses, clothing and props, derived from the world of the sex industry to sell things, whether that is music or some other product.

Shadow health minister Diane Abbott recently voiced concern about the commercialisation and sexualisation of childhood, but I don't think the problem is to do with childhood. The real issue is the way the commodification of sex and its ascendance as a prime marketing tool has made it so integral to consumer culture that there are few places we do not find it being used.

One recent Ofcom survey found that 11% of parental concerns over pre-watershed programmes involved music videos. J-Lo's performance was pretty unexceptional. It had the flavour of something we've all seen a thousand times before and, in its desperate, high-energy delivery of a parody of sexual poses, came across as bland and unsexy.

At the end of the singer's act, judge Amanda Holden quipped: "Well, J-Lo's arse – I just wanted to bite it." But the impression I got from this was one of someone trying far too hard. In the real world, where sex is prompted by hormones and chemistry, we don't really need this performance. Where it is needed, in all its athleticism, is in the world of commerce, in the entertainment industry, desperately trying to reel in viewers and sales.

It is hard to know how to resist this. Many people accept that this is the way things are, and even enjoy it. The complaints about Rihanna, J-Lo and Christina Aguilera have represented small blips by comparison with the tidal wave of complaints Ofcom received after the Shilpa Shetty row, when many viewers were offended by what they saw as racist bullying of Shetty by her Celebrity Big Brother housemates.

For the most part, we just sit back and enjoy this gleeful pornification. And in doing so, we forget it is not just our kids' attitudes towards sex that are being distorted, it is also our own.