Evidence shows that a combination of comprehensive sex education and access to birth control appears to decrease the rates of unintended pregnancies among teenagers. A meta-analysis that compared comprehensive sex education programs with abstinence-only programs found that abstinence-only programs did not reduce the likelihood of pregnancy, but rather may have increased it. Numerous studies show that curricula providing accurate information about condoms and contraception can lead to reductions in the risky behaviors reported by young people as well as reductions in unintended pregnancies and STIs. Programs that teach only abstinence have not been shown to be effective.