A new report warns that an increase in the use of drugs and alcohol and risky sexual behaviour among young people is contributing to a "sexual health crisis".
The increase in sexually transmitted infections (STIs) and high levels of teenage pregnancy in the UK are "disturbing" and there is "no doubt" alcohol and drugs enhance sexual activity, it said.
The Independent Advisory Group (IAG) on Sexual Health & HIV, which published the report, calls for more action to deal with the crisis facing Britain's teenagers.
It said young people are exposed to conflicting messages, with "explicit or subliminal" advertising and coverage of "celebrity" behaviour being prevalent, while other information is restricted.
"For example, there are restrictions on advertising condoms prewatershed, and on showing a picture of a condom out of its wrapper. Our young people are therefore receiving distorted messages," it said.
The report claims young people engaging in risky sexual behaviour are at greater risk of contracting an STI, becoming young parents, failing at school, building up longer-term physical and mental health problems and becoming addicted to alcohol and drugs.
It states that STI rates have risen greatly over the past 12 years, with chlamydia and HIV both increasing by 300%, gonorrhoea by 200%, and syphilis by 2,000%.
Baroness Gould, chairman of the IAG, said: "We applaud the various awareness campaigns for young people around sex, drugs and alcohol but they are not enough in isolation.
"As well as health promotion and prevention messages, all involved should review the areas that potentially encourage the young to use alcohol and drugs, with the associated impact on sexual activity."