British teenagers are the most sexually active in Europe and children should be taught about contraception to stem the problem of teenage pregnancies, a report published on Monday said.
A study by the Institute for Public Policy Research (IPPR) found that 38 percent of British 15-year-olds had had sex in the period from 2001-2.
That compared to just 15 percent in Poland, 16 percent in Spain and was also far greater than the countries with the second highest proportion - Sweden, Finland and Germany.
In addition Britain had the highest rate of teenage births, an average of 26 live births per 1,000 women aged 15 to 19.
Sexually related diseases such as Chlamydia and herpes had also risen amongst young people, with one in three 15-year-olds admitting they didn't use condoms.
Last month the British government said it would target "hot spot" areas for teenage pregnancies and encourage local authorities to focus their efforts on cutting the numbers.
But the IPPR said despite previous government initiatives, progress had been slow. It called for all children to be taught about the importance of contraception in their last year at primary school, when they are 10 or 11 years old.
Julia Margo, senior research fellow for the IPPR, said there had been a dramatic fall in the last 50 years in the average age people first had sex.
"The proportion of young people who are sexually active before the age of consent has risen from less than one percent to 25 percent," she said.
"Our education system must respond in kind and start teaching children about the risks involved in sex before they even consider taking those risks."