Front covers become more and more explicit as teenage readers' appetite for lurid details reaches insatiable levels. Magazine editors and publishers are getting desperate in attempts to satisfy readers' demands for more glimpses of nudity and more behind-the-bedroom-door details. And the Beckhams are laughing all the way to the bank.

Posh 'n' Becks are the new sex. A few years ago, there was general frenzy in Britain at the sexual content of teenage magazines, prompting complaints and fears that articles in them were introducing and encouraging young readers to experiment sexually. Magazine editors and publishers were accused of using sex to sell more copies.

That was in 1996, and four years later sexual content has been partly eclipsed by celebrity gossip. The weekly celebrity gossip mags like NOW, OK and the long established Hello dominate the news stands and prove very popular among with teenage readers. Pictures of Posh Spice and hubby are now used to sell those same magazines.

Celebrities Zoe Ball, The Hair (aka Jennifer Aniston), Britney Spears and any of America's young teen drama stars guarantee a bumper sell-out issue for the traditional magazines. These girls are the new role models for younger generations. Sugar, J17 and Bliss are among the popular and well established titles targeting the teenage market. Meanwhile, magazines such as Cosmopolitan and Company are positioned to appeal to a broader spectrum of young women, but definitely draw readers from as young as 14.

While the teenage magazines have certainly got less sex in them than they did four years ago, the magazine marketplace has become more streamlined and publications have concentrated more on niche market segments. It remains the case that girls tend to read the magazines that are supposedly targeted at older readers: 16-year-old girls don't necessarily want to read the material that publishers say is for 16-year-old girls.

Bliss and Mizz are the magazines for the younger teens, finding broad appeal with 12- to 14-year-old girls. The layout and design are bright and colourful, with lots of gossip and celebrity interviews. Mizz is published every fortnight and Samantha Mumba is this issue's "Exclusive". The articles are faddish and frivolous and make for light-hearted reading. Sex doesn't feature strong here; boys, crushes, romance and how-to-advice get a good spread though.

Fifteen and 16-year-old girls demand a more sophisticated product. They tend to prefer magazines aimed at the more experienced late teen and 20-something market. Starting with J17 and Sugar, and on to the more grown-up titles of Company and Cosmopolitan, their hottest titles tend to be pretty hot indeed.

Promises of nudity and more sexually explicit articles have long graced the front covers of young-women's magazines. "Saucy sealed section! Your X-rated guide to his raunchy bits" is on the front cover of November's Company magazine - highlighting a special pull-out-and-keep section that sounds more exciting than it really is!

B Magazine promises "Your sex fantasies tried and tested", while Cosmopolitan splashes more pictures of naked men.

Is this a cause for alarm or just big headlines? The British Teenage Magazines Arbitration Panel (TMAP) was established back in 1996 as the magazines industry's self-regulatory body, to ensure that the sexual content of teenage magazines is presented in a responsible and appropriate manner.

Kate Wellings is co-author of one of the largest study of sexual attitudes and lifestyles ever carried out in Britain, Sexual Behaviour in Britain, and has also undertaken an examination of the role of teenage magazines in the sexual health of young people.

"The charge is sometimes made that young women's magazines are dominated by sex; that the subject takes up an ever increasing proportion of their content. Yet a review of articles in Bliss in the last few months showed just 8 per cent of articles to be about sex, only half of that devoted to fashion. In Just Seventeen (J17) during this period, the space allocated to articles on sex was only marginally higher at 10 per cent, and again the subject received less coverage than fashion," Wellings wrote in the report. She suggests that the culture's preoccupation with sex in teenage magazines is, in part at least, a response to changing sexual values among young people.

Teenage girls enjoy these articles, and consider them fun to read. They buy magazines for entertainment and while certain articles are tacky and just plain stupid, there is also an education element to them. Teenage girls say they learn a lot about sex, relationships and life from these magazines, and find answers to the questions they are sometimes too embarrassed to ask.

So do the teen magazines accurately reflect the lives of their readers? There's sections devoted to "chillin' with your friends" looking at the best music to chill to, hip clothes to buy, tracking trends from abroad and the world of astrology and horoscopes. Editorial teams at the top titles are usually young and chase new trends as they happen.

And really, there's not a lot of differences between the titles. This months issue of supposedly grown-up Cosmopolitan has "Gwyneth, Madonna, Zoe, Jennifer - who's your celebrity soulmate?" There's always a "Steal the celebrity style" section and a drip-feed of what Posh is doing, what she's wearing and what she's saying.

Sixteen-year-old girls have no brand loyalty. They want Posh 'n' Becks, celebrity gossip, saucy stories and decent freebies. And they buy whatever magazine is offering the winning package this month.