Michael Gove has has rejected a call from Nick Clegg, who wants the government to update sex education guidelines, to teach teenagers about the "menacing" threat of internet pornography.

The education secretary said on Thursday technology moved so quickly that teachers should be trusted to make their own judgments and speak to experts.

Gove spoke out after the deputy prime minister said the guidance on sex education, which was last written in 2000, should be updated to take account of the "explosion" in internet pornography. Clegg made the comment on his weekly LBC Radio phone-in programme after a 17-year-old woman said that young people faced pressure to conform to what happens in internet pornography.

The caller said of the sex education lessons at her school: "It is quite old fashioned. There's nothing really about the social side. It is very biological. We were watching VHS videos in our classroom."

Clegg said: "I have heard this from quite a lot of teenagers and young men and women: this explosion in internet pornography and particularly the indirect pressure it seems to bring to bear on young women is a new problem, which clearly wasn't there when the guidance was last written in 2000. The guidance should be updated. The last time the guidance was changed was 13 years ago and the world is a very different place now. In many respects, it is a more liberating place, not least because of the internet, [but] it is also a more menacing place, particularly but not only for young girls.

"I suspect all parents want their teenage sons and daughters to be not just given the biological facts of life, but also to be given some sex and relationship guidance. It doesn't matter what school they go to – that should be made available to them. At the moment there are lots of schools – academies, free schools and so on – who don't need to follow the guidelines, even the outdated ones."

Clegg said his Tory coalition partners disagreed with him: "This is not shared across government. I haven't been able to persuade Michael Gove and the Conservatives to move all the way on this. They have moved some of the way, so there is going to be guidance in the national curriculum on IT classes, which has some bearing on this. And the national curriculum, even though that doesn't need to be taught by all schools, does at least raise the expectations that schools should teach this. And Ofsted, very usefully, will be showing what is the best practice in all of this.

"Michael Gove has got a very well expressed and articulate view that schools shouldn't be burdened with too many directives from central government. In general terms, I support – particularly after the excessive micro-management by previous Labour governments – his wish to liberate teachers and headteachers to do what they judge is best for their children.

"I just happen to think in this instance, given how menacing this is, particularly for young girls, this is an area where we do need to update the guidance and raise the expectation that all schools do this properly in the classroom."

Gove told The World at One on Radio 4 that in a recent review of sex and relationship education, experts had advised him against updating the guidelines. "The point they made to us is, rather than attempting to update guidance when technology changes so rapidly – a year ago we wouldn't have known what Instagram meant – the most important thing is to make sure we provide the resources teachers need," he said.

"We trust teachers to deliver sex and relationships education in the right way. But we give them the opportunity to talk to experts."