The DNA of thousands of children is already being kept on Scotland's national database, The Herald can reveal.

New figures show the DNA of 4790 teenagers aged 16 and younger is held on the system.

This has raised concerns with civil rights groups which believe further debate is required about how the database is used.

The database holds the personal profiles of 226,871 Scots. Only 123,637 of these samples belong to convicted criminals; the remainder are held because of ongoing criminal investigations or because the person has been accused of a particularly violent or sexual offence.

Of those samples, 103,234 are pending because of an ongoing criminal investigation, 193,377 are from men and just 33,494 belong to women.

Scotland has rejected proposals to create an English-style national DNA database containing any non-convicted samples but there are moves to change the system.

Professor James Fraser, the head of Strathclyde University's Centre for Forensic Science, is carrying out a review of the database commissioned by the Scottish Government.

One of the areas he has been asked to look at is whether DNA samples belonging to children who commit sexual and violent offences, but who go before a children's panel, could be kept by the police.

Police are allowed to store only the DNA of children who are convicted of violent or sex crimes in an adult court. The proposal has caused consternation.

Police forces in England and Wales are believed to have kept the DNA of more than 100,000 innocent children.

But civil rights groups said they were not aware that so many were kept in Scotland.

John Scott, a civil rights lawyer and chair of the Howard League, said: "The number of children already on the database seems particularly high. Most people would generally see a DNA database as a good thing but that is because they assume it will only feature the profiles of the guilty."

Authorities in Scotland are only allowed to store permanently the DNA of people convicted of crimes. They can keep the DNA of those charged with, but not convicted of, serious sexual and violent offences but only for a restricted time.

The DNA database is managed by the Scottish Police Services Authority.

A spokeswoman said: "Legislation allows an individual's DNA to be retained in three broad circumstances: permanently following conviction; temporarily if the person is accused of sexual or violent offences even if not convicted or for so long as the person is part of an on-going investigation for which the DNA was taken. All samples are analysed and the profiles stored on the Scottish database as well as being sent to the National DNA Database.

"All Scottish profiles are inserted and removed from the national database under the terms of Scottish legislation."