Traditionally, adolescents were not given any information on sexual matters, with discussion of these issues being considered taboo. Such instruction as was given was traditionally left to a child's parents, and often this was put off until just before a child's marriage. Most of the information on sexual matters was obtained informally from friends and the media, and much of this information was of doubtful value. Much of such information was usually known to be deficient, especially during the period following puberty when curiosity of sexual matters was the most acute. This deficiency became increasingly evident by the increasing incidence of teenage pregnancies, especially in Western countries after the 1960s. As part of each country's efforts to reduce such pregnancies, programs of sex education were instituted, initially over strong opposition from parent and religious groups.
The outbreak of AIDS has given a new sense of urgency to sex education. In many African countries, where AIDS is at epidemic levels (see HIV/AIDS in Africa), sex education is seen by most scientists as a vital public health strategy.[citation needed] Some international organizations such as Planned Parenthood consider that broad sex education programs have