The WHO recently analyzed 35 studies of sex education programmes in schools around the world. The analysis concluded that sexual education does not lead to earlier or increased sexual activity. Of the 35 studies cited, 16 found that the onset of sexual activity was delayed among youth with sex education, and among those already sexually active there was a decrease in the extent of sexual activity or increased use of 'safer sex' practices. The survey also found that programmes promoting both delayed sex and protected sex were more efficient than programmes that stressed abstinence only.