Next week the V&A opens an exhibition called Fashion v Sport, profiling the relationship between the sports and fashion industries - a relationship that seems to be flourishing despite the habit of many of today's sportsmen and women of wearing less and less.

Recently the New York Daily News ran a spread of photos showing rugby players from the New Zealand and South African national sides playing a match, starkers, on a windswept New Zealand beach. Disappointingly, it turned out that the players showing us their tackle were not in fact Boks and All Blacks, but local amateurs taking part in a beery annual “Naked Rugby” event.

But who can blame the media for getting over-excited? After all, last year the Rugby World Cup was advertised with posters on the Tube of snogging, scrumming rugby players. And then there are footballers such as Freddie Ljungberg and David Beckham (below, in the Motorola RAZR2 advert in 2007) spreadeagled across the side of buses.

Almost everywhere you look, sports, advertising and fashion seem to have jumped into bed to produce a spornographic money shot. Sports stars have become sporno stars. How did this happen? What does it mean? And where can I get hold of a pair of those pants?

Ironically, the only unconvincing aspect of the snogging scrum campaign was the relative unattractiveness of the faux rugby players compared to the pumped, shaved perfection of the real thing. The Parisian team produce an arty soft-porn calendar, called Dieux du Stade, featuring lovingly photographed nude players soaping each other up in the showers. A great success. It sells like, well, hot rugby players.

In the run-up to the last football World Cup the fashion label Dolce & Gabbana commissioned the photographer Mariano Vivanco to snap members of the Italian team all oiled up and ready for us in the changing rooms, wearing very skimpy - and stretchy - D&G briefs. The results were splashed across prime advertising sites. In hindsight, the world was grovelling at the Italians' feet from that moment on. The Spanish winners of Euro 2008 have yet to pose glistening in thongs, but with studs such as Fernando Torres and Iker Casillas in their stable it can only be a matter of time.

To get our attention in an age of broadband jadedeness, men's fashion advertising has to promise us nothing less than an immaculately groomed, waxed and pumped group session in the showers.

And if this sporno looks a bit gay, that's probably because it's meant to. Partly because it made you look, partly because gay men are a loyal niche market and also taste-formers - especially when it comes to consuming the male body (Mr Dolce and Mr Gabbana are themselves famously gay).

It's also partly because it seems to turn on the ladies in the same way that girl-on-girl action does their boyfriends. For an athlete nowadays, having a big gay following no longer necessarily means looking over his shoulder worriedly, but instead turning round and winking playfully.

Both Beckham and Ljungberg have posed in gay magazines, the beefy former England rugby ace and married father of two Ben Cohen has brought out a nude calendar marketed at gay men and talks about “embracing my gay fans”. Some, such as Becks and Welsh rugby glamour-boy Gavin Henson, have even argued over them. “I think I have lost a lot of my gay fans to Gavin,” Beckham once said. “It is a shame, as I really love them.”

Being equal-opportunity flirts, today's sporno stars want to turn everyone on. Sportsmen, like porn stars, are by definition show-offs. Besides, it also means more money, more power, more endorsements, more kudos.

Fashion is more than happy to indulge them. Athletes represent everything that is desirable today: youth, vigour, success, health, fitness, looks, fame - and also the sweaty shorthand for all these things: sex. What's more, as highly paid “pros”, their bodies are already what all men's bodies are supposed to be these days: hot commodities. If athletes with hundreds of thousands of fans - gay and straight - are willing to tart themselves up this way, why bother with silly, skinny male models?

Naturally, all the sporno stars flirting with gayness are officially heterosexual. Team sports are still not the best place to openly bat for the other side, not least because it might cost you one of those lucrative gay-looking sporno endorsement deals. Virility is still considered to be officially hetero. (This holds true even in gay porn - where many stars are, like sporno stars, only “gay for pay”.)

But there's no denying how dramatically attitudes towards the sporting male body have changed as a result of sport's collision with the world of fashion and celebrity. Sporting male heroes now adopt sex-object poses on the side of buses that were once seen as girly, slutty or homosexual. Or, what was once much the same taboo in the male mind: passive.

As one outraged, middle-aged - and rather plain looking - BBC sports presenter thundered recently in The Sun about Beckham's Armani-clad giant package: “You've got money, status, respect and fame - and then someone says: 'Armani want you to do a picture wearing tight white pants with your legs as wide open as England's defence.' Why would you say yes?” Actually, in a spornographic age, the question should really be: why on earth would you say no?

The Fashion v Sport exhibition runs from Aug 5 to Jan 4. The catalogue, edited by Ligaya Salazar, is published by V&A Books for £19.99. www.vam.ac.uk

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