The national DNA database contains the profiles of almost 40,000 innocent children, the Home Office has revealed.
Junior minister Meg Hillier said the profiles of over 39,000 ten to 17-year-olds, who "had not been convicted, cautioned, received a final warning/reprimand and had no charge pending against them", were now on the database.
The number is also rising rapidly. Just two years ago, the number of innocent children on the database was 24,000.
The criminal age of responsibility is over ten. The DNA database contained the profiles of 49 children aged nine or under, and 680 children who were aged 10.
Hillier was responding to a parliamentary question from Tory MP Grant Shapps, who has campaigned against the details of innocent people being held on the database.
Hillier said figures obtained from the National DNA Database (NDNAD) and Police National Computer (PNC) in April showed that there were 349,934 DNA profiles relating to under-18s. The number has risen since April.
Because of replication rates, this was equivalent to 303,393 individual records. Of these, 87.1% had either a conviction, caution, reprimand or had received a final warning from the police.
She said 39,095 (12.8%) had not been convicted, cautioned, received a final warning/reprimand and had no charge pending against them.
The Liberal Democrats said the figures showed that the government was "building a national DNA database by stealth" and called for a parliamentary debate on the issue.
There are a total of 4.2 million people on the National DNA Database, including 1 million profiles from innocent people.
A government advisory body last month said the details of innocent people should be removed from the database. The government said it would consider this, but has so far made no firm plans to do so.