Warwickshire Police are taking too many DNA samples from children, according to a national charity.
The Howard League for Penal Reform found that officers took swabs from 599 boys and girls aged 17 or under during 2011.
Many of the children required to give a sample will not have been charged with a criminal offence.
Under current rules, police can retain indefinitely the DNA of anyone they arrest for a recordable offence.
The league’s chief executive, Frances Crook, Chief Executive of the Howard League for Penal Reform, said: “Children who get into trouble with the police are usually just up to mischief. Treating so many like hardened criminals by taking their DNA seems excessive.”
Warwickshire Police says it is acting in accordance with current legislation on the matter.