It also found a link to underage sex and the likelihood of smoking, consuming alcohol and taking drugs and claimed that many children from the age of 10 accidentally accessed "violent and sadistic imagery" while undertaking legitimate research.
The report called for compulsory sex and relationship education in primary and secondary schools, including modules on the dangers of pornography.
The study - carried out by the universities of Middlesex, Canterbury Christ Church, Bedfordshire and Kent - was based on analysis of 276 pieces of research.
Netsafe chief executive Martin Cocker said it was difficult to protect young children from graphic images online because while you could put a filter on your computer, you couldn't do that to every one they used.
"We all wish we could have a fool-proof way of protecting children from harmful content while at the same time allowing them to have all the benefits of technology, but the truth is risk is part of the equation.
"You've got to be ready to explain to children the reality of what that content is and what it isn't, and that conversation is happening at a much younger age than it would have a generation back."
Mr Cocker said similar research was being conducted at the University of Auckland and expected its results would be similar to the English study.
- Daily Telegraph UK; staff reporter