For parents, it is a frightening and disturbing concept.

The idea that teenagers and children might be using modern technologies to exchange texts or messages containing nude or semi-naked images of themselves or their peers challenges ideas about innocence, yet can lie at the boundaries of what is normal exploration and what is a crime.

Figures revealed by a Freedom of Information request today show some of the children being identified by councils and police forces as involved in this issue are very young.

They also demonstrate a considerable confusion about the issue: half of Scotland's police forces are unable to identify cases because "sexting" is not a specific offence. Meanwhile half of Scottish education departments which responded said they did not keep records of incidents.

In some cases this is because their policy is not to, others said any cases would be dealt with internally, while some said incidents would be referred to the police.

The definition of sexting used in requesting the information was: "The sharing of sexually explicit information, including photos, using mobile phones or web-based messaging."

According to research being highlighted today by the child protection agency With Scotland, 40% of the UK's 14 to 16-year-olds said their friends have engaged in such behaviour, while 27% said they were aware of it happening "regularly" or "all the time".

A separate study of 120 pupils in England aged 13 and 14 found sexting was considered by that age group to be common practice.

Kelly Stone of Stirling University has produced a research briefing and factsheets for professionals about the problem, which will be published at an event on child protection and the internet being held at Stirling University today.

The briefings warn that some young men appear to be bullying or coercing girlfriends into taking and sending sexual images.

One study found images of girls could become a form of currency between boys, Ms Stone said. The images can end up being circulated widely and used for bullying.

"It is alarming. Girls are reporting that they keep getting pressured, often by boys they know, and some give in. The boy may well be being coerced as well in that it is seen as something they are expected to do by their peers.

"But while there are negative consequences for the girls, for the boys research seems to show that the more sexual images they have, the better it is for them."

The issue is horrifying for parents, Dr Stone said, partly because of the ease with which such activities can happen covertly – given the ubiquity of mobile phones and tablet computers with cameras built in. "Because of the private nature of smartphones and tablets, it can be done very secretly.

"There are different definitions of sexting and that can make it hard to be sure how widespread this is. Some people would say it was a police issue because it is an unlawful act. But if young people assume it is just part of what they do, then other services may need to become more involved.

"Research seems to be suggesting it is seen as natural, or expected practice. That would indicate it is something for schools and other universal services to consider."

Teachers and other professionals working with young people could do more to prepare children to use the internet safely and be responsible about what they see and put online, Ms Stone said. Peer education might be the best approach.

"We need to be thinking very carefully about how we are working with young people to discuss this. We have peer mentors working in some parts of Scotland and it can be easier for young people to talk about sexual risks and behaviour between each other."

Ethel Quayle, senior lecturer in clinical psychology at Edinburgh University, will speak at today's event about research she is currently carrying out on the impact of sexting on adolescents in three European countries, Sweden, Germany and the UK. This will look at the context in which images were created and the consequences they have had for individuals.

The variation in what is covered by the term is problematic, she said. "This can happen in the context of a coercive relationship or a romantic relationship with another young person, or it can be part of grooming someone for abuse. The boundaries around what is exploratory behaviour and what is problematic are very blurry and in some cases it is better not to turn this into a criminal justice scenario."

Colin McKerracher, Chief Constable of Grampian Police, said the figures from his force – an average of 10 cases a year – had resulted in a range of outcomes. "In some cases we would just warn people of the dangers, in a more concerning case we would refer a child to the children's reporter. If there is a wider background of risk there might be a situation where a case is reported to the procurator fiscal. Even then that might just result in a procurator fiscal warning."

Looking at what offence has been committed can also throw up surprising results, he added. "Just now, under the communications act, if you have sent a naked photograph of yourself to your boyfriend it is you that has committed the initial offence. If he then sends it on, he is committing an offence.

"If your parents find it and send it to the boy's parents, saying 'look what he's done' then in pure terms they are offending too."

Mr McKerracher is also a member of the steering group of With Scotland, the body holding today's conference in Stirling. The need for a clearer look at this and other internet child protection issues is evident by the demand for the event from professions, he said it is oversubscribed and a further event is to be held later in the year.

"Professionals are coming across more and more situations where young people are at risk or have been harmed by experiences with the net.

"This is an issue that can harm young people and all the professionals, including social work education police and health are becoming increasingly aware of it."