Sex abstinence programmes do not stop risky sexual behaviour or help in the prevention of unwanted pregnancy, a research team has concluded. The Oxford University team reviewed 13 US trials involving over 15,000 people aged 10 to 21. They found abstinence programmes had no negative or positive impact on the rates of sex infections or unprotected sex, the British Medical Journal said. Abstinence programmes are popular in the US and have supporters in the UK. A UK branch of the US Silver Ring Thing was set up four years ago to promote sexual abstinence among young people. However, such groups have so far failed to gain the foothold they have in the US where a third of the President's HIV budget is given to abstinence programmes. The latest study, which included trials comparing young people attending abstinence-only programmes against those receiving no sex education, raises questions over whether they work in developed countries. Researchers found none of the abstinence-only programmes had an impact on the age at which individuals lost their virginity, whether they had unprotected sex, the number of sexual partners, the rates of sexually transmitted diseases or the number of pregnancies.