Government figures show sexually transmitted diseases among children have increased by 58% in the past five years.
The figures from Genito Urinary Medicine clinics and the National Chlamydia Screening Programme show the number of under-16s in England diagnosed with sex infections increased from 2,474 in 2003 to 3,913 in 2007.
However, the biggest increase was in cases of chlamydia, which rose by 90%, although cases of genital herpes were up by 42% and genital warts by a third.
The figures, which were released in a Commons written answer to Liberal Democrat health spokesman Norman Lamb, also show cases of syphilis doubled from three to six.
Testing for chlamydia has increased since April 2003 when the National Chlamydia Screening Programme was introduced.
The programme tests for the infection in community contraceptive clinics, some further education colleges, and more recently through postal testing kits and pharmacies.
A Department of Health spokesman said: ‘The National Chlamydia Screening Programme has been rolled out throughout the NHS since 2003.
‘The programme has helped us to screen an increasing number of people for chlamydia. Since 2008, all primary care trusts have been reporting to the programme, which accounts for the recent increase in reported cases.’