Children are being damaged by readily available pornography and books such as Fifty Shades of Grey, teachers have warned.
Teacher Niamh Sweeney, from Cambridgeshire, said she was concerned that the best-selling book normalises abusive relationships.
She said: "It describes a violent and abusive relationship where a young girl admits to being hurt and not enjoying it but agreeing to it because she knows he likes it."
She was so concerned that it prompted her to speak to her lower sixth students about sex and relationships.
At a conference in Liverpool, members of the Association of Teachers and Lecturers called for extra training to help them give lessons about pornography.
Teachers warned that viewing explicit images has become the norm for students as young as 11, and it risks damaging their future relationships and expectations of sex.
One teacher said she knows of a girl who was persuaded to perform in an amateur pornographic video at the age of 13.
She told the conference: "As a teacher of teenage girls and the mother of a teenage daughter I am absolutely sickened by that thought.
"As educators we must ensure that pornography does not become so normalised that youngsters expect it to be an unquestionable and significant experience of their daily lives."
James Schlackman, an ATL member from Berkshire, said the porn that is available today is aggressive and bordering on abusive.
He added: "It doesn't show normal sexual behaviour, but there is so much of it that to young people, without the benefit of experience, it appears to be normal.
"Young people today are being exposed to dangerously unrealistic portrayals of sex that, if emulated, may end up damaging the relationships they form both now and in later life."