As sexually transmitted infections increase amongst the young, and UK teenage pregnancy rates remain the highest in Western Europe, children's activists say the answer is yet more sex education.
In a letter to the The Times, charities, politicians and celebrities have said that schools, including faith schools and city academies, should not be allowed to choose what kind of sex education they provide.
The letter says, "No school should be able to opt out of delivering good Sex and Relationships Education to their pupils (including primary schools, faith schools and academies), which should be taught throughout a pupil's time in education."
But critics say decades of sex education has clearly failed. In 2005, there were 42,325 conceptions in the UK among under-18s, with 46% being aborted. The numbers do not include those pregnancies ended by the morning-after pill.
In November the Health Protection Agency said that one in ten young people screened for Chlamydia were found to have the infection.
