School based sex education, delivered before the minimum school leaving age remains the most effective way of universally, comprehensively, and uniformly targeting adolescent population. (1) Worldwide, approximately half of 16-year-olds are sexually active and have partner turnover which facilitates the spread of STIs, is at it's highest amongst young people (2) Approximately 60% of all new HIV cases are among young people (3) and more than 90% of these infections are due to sexual transmission (4) Despite a marked increase in contraceptive use at first intercourse
78% of adolescent in the USA used a contraceptive at first intercourse in 1995 compared to 48% in 1982. Consistent condom use is generally low amongst young people (5) In the USA for instance, 25% of sexually active adolescence contract a STI each year and more than half of all new HIV infections occur among persons under the age 25 representing about 20,000 new HIV cases each year (6) Moreover it is estimated that about a quarter of HIV infected individuals in the United States are undiagnosed and unaware that they have HIV (7) In addition, 10% of all adolescents and 19% of sexually active adolescents in the United States become pregnant each year (70) These statistics demonstrate the need for more effective sexual health education for young people.
The prevalence of sexually transmitted infections (STIs) is increasing in the teenage group. Sexually active young people are vulnerable to STIs and prevalence among the young is increasing: 20-30% of females diagnosed with an STI have another within 18 months (8) Data from UK studies by Schofield (1965) and Farrell (1978) on numbers of 16 to 19 year olds reporting having intercourse before the age of 16 together with data from a more recent and very large study by Welling et al.