In high school sex education classes, Sarah had learnt about contraception and sexually transmitted infections. There was also some discussion about intimacy and relationships, but nothing to warn her of a disturbing new trend: many young men are watching pornography and then replicating some of the aggressive behaviour they observe with their sexual partners.

When researchers Dr David Corlett and Maree Crabbe filmed 140 interviews with young people, academics and those working in the porn industry recently, they found that pornography was not only widely accessed by teenagers but had become more violent in recent years, often portraying coercive, abusive treatment of women.

Ms Crabbe says many young men watch thousands of pornographic images before their first sexual experience, and this is shaping how they think about and experience sex. ''They, and their partners, can have some costly experiences because of this,'' she says.

Dr Debbie Ollis, an expert on sex education at Deakin University, is working with the two researchers to help them to translate their findings into resources for universities training sex education teachers and for schools. ''Teachers must have the skills to address this confronting issue,'' she says.

Ms Crabbe says school-based pornography education might sound controversial, but argues that young people urgently need help to critique pornography's representations of gender and sex, and to help them distinguish between what they see and reality.

''Pornography is now our most prominent sex educator,'' she says. ''And while Victoria has good sex education relative to other states, it varies in quality. Some schools do fantastically and others don't, but even those that do it well face a significant challenge because of the mainstreaming of hard-core pornography.''

As a youth worker with Brophy Family Youth Services, Ms Crabbe became aware that the marginalised young men she met watched a lot of pornography and had unrealistic - and often troubling - expectations of their sexual partners. ''Some expressed surprise that their partners did not do what they asked without hesitating and did not want to follow the 'script' of pornographic videos.''

Ms Crabbe joined with Dr Corlett, an academic and writer who won plaudits for his recent role in the reality television series on refugees Go Back to Where You Came From, to interview many more young people.

The video interviews for their Reality and Risk research project provide frank and thought-provoking footage for a documentary film, which has been funded by philanthropists and will be completed in a few months.

The researchers hope the documentary will be screened on television and will prompt widespread debate. Some interview excerpts will be used in audio-visual classroom resources.

They are also developing teaching materials, where students are presented with diverse scenarios to discuss, as part of an update of the Catching On sex education resources widely used in schools.

Dr Ollis says many third-year primary and secondary teacher trainees at Deakin University were shocked when she showed the filmed interviews as part of their sex education training. One young man admitted he watched pornography but had not - until now - registered how much of the content was violent and gave no sense of what women might like. ''For the first time he realised that it provided negative sex education,'' she says.

Dr Ollis says the research helped the trainee teachers to develop age-appropriate teaching resources on topics such as sexting (texts with sexually explicit content).

She sees such material as essential. ''Fifteen years ago schools regarded sexual diversity as taboo and now it is integrated into the curriculum. The gender-based violence in pornography also has to be addressed.''

The research confirms the findings of a 2006 Australian study of those aged 13 to 16 which found that 92 per cent of boys and 61 per cent of girls had been exposed to pornography online.

''Every young person we interviewed told us that pornography is a significant part of youth culture and particularly of young men's lives … and at the same time the pornography has become harder, rougher, more hard-core,'' Ms Crabbe says.

The researchers travelled to the US and Budapest (the sources of much pornography), interviewing industry veterans such as Los Angeles-based, Hungarian-born porn performer Anthony Hardwood, who noted how in his 13 years in the business there had been a shift from ''lovey-dovey sex'' to Gonzo sex, a cinematic style where a hand-held camera is used to film what is often a violent scene.

They also interviewed young female performers, who confirmed that pornography had become more violent in recent years, and that they had to pretend to enjoy being treated badly.

Ms Crabbe says pornography also fails to promote safe sex, with only about 10 per cent of videos depicting the use of condoms. ''It is also a poor educator when it comes to consent, with the young women we interviewed saying some young men who watched porn attempted sex acts, such as anal sex, without asking,'' she says.

One young woman summed this up: ''I think that men think that they'll test, that they'll see if they can do whatever they see in porno … a past person that I've been with assumed that I'd enjoy something that he'd seen and it almost feels hard to say 'no' .''

As a result, Ms Crabbe says some young women are being coerced into sex that they do not enjoy. ''The porn erotic is so 'normal' that women may not see that this construction of sexuality is not about her dignity, respect … or her pleasure,'' she says.

While many parents may believe their child has never seen pornography, a 2003 Australia Institute study found that 84 per cent of boys and 60 per cent of girls had been accidentally exposed to sex sites on the internet.

''This reflects the aggressive marketing of internet pornography, including through the use of involuntary and persistent 'pop-ups' and games that become increasingly sexually explicit as young players progress through levels,'' Ms Crabbe says.

Pornography has also altered what is regarded as looking erotic. Young women, and some young men, attribute their decision to remove pubic hair to the influence of pornography. The young people interviewed also talked of comparing their bodies - and those of their partners - to the oversized breasts and penises depicted in pornography.

Ms Crabbe says the rates of cosmetic surgical interventions such as labiaplasties have grown dramatically in recent years, with some researchers drawing links between this and the pervasiveness of pornography.

Students can develop skills to critique this in sex education classes, Dr Corlett says, but it should also be reinforced in other curriculum areas such as English or humanities subjects.

''Young people must have the skills to reject a sexuality that eroticises degradation and violence as it undermines their ability to have healthy and fulfilling intimate relationships,'' he says.