"In a single act of unprotected sex with an infected partner, adolescent girls have a 1% chance of acquiring HIV, a 30% chance of getting genital herpes.
Britain is facing a major teen sex health crisis.
Britain is facing a major teen sex 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, Independent Advisory Group (IAG) on Sexual Health and HIV said.
It said young people are exposed to conflicting messages, with "explicit or subliminal" advertising and coverage of "celebrity" behavior being prevalent, while other information is restricted.
"For example, there are restrictions on advertising condoms pre-watershed, and on showing a picture of a condom out of its wrapper. Our young people are therefore receiving distorted messages."
(Watershed is the time after which adult content is allowed to be aired on TV.)
The IAG report said young people engaging in risky sexual behavior 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.
A recent UNICEF report put the UK at the bottom of a table of 21 countries for children's well-being.
It found that more children in the UK have had sexual intercourse by the age of 15 than in any other country, more have been drunk twice or more times aged 11, 13 and 15 than in any other country, and they are the third-biggest users of cannabis.
Professor Mark Bellis, head of the centre for public health at Liverpool John Moores University, is quoted in the report.
He describes the link between alcohol, drugs and risky sexual behavior as "fuel for a sexual health crisis".
The study said alcohol consumption needs to be cut, both by making it difficult for teenagers to buy it and by getting messages out at a young age.
It said there is a "need to realize what it is like to be young today", including that young people have desires to "experiment and explore" and "try something new".
Efforts should therefore be made to ensure young people receive "clear and factual information on the effects of drugs, alcohol and sex, and exposing the myths".
Such elements should be part of compulsory education, rather than the non-statutory arrangement in schools as at present, the report said.
One recommendation was for the Government and stakeholders "to encourage a review of advertising regulations on condoms - for example, to remove the restrictions on showing condoms before 9pm (except Channel 4, which can show condoms from 7pm) or unwrapped condoms before 10.30pm."
The report said STI rates have risen greatly over the past 12 years, with chlamydia and HIV both increasing by 300%, gonorrhea by 200%, and syphilis by 2,000%.
"In a single act of unprotected sex with an infected partner, adolescent girls have a 1% chance of acquiring HIV, a 30% chance of getting genital herpes, and a 50% chance of contracting gonorrhea."
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.
"We recommend that the Government works with manufacturers, advertisers and broadcasters to look at issues like advertising alcohol to the young and equalization of children's toys.
"As part of this - and as a bare minimum - the IAG believes schools must provide PSHE (personal, social and health education) that helps young people negotiate today's personal, social and health issues.
"This should be a statutory requirement."
Health Minister Caroline Flint said the Government would be examining the report.
She added: "We are continually looking at new ways of working to ensure a joined-up approach that places the individuals, in this case young people, at the heart of the work we are doing."
Simon Blake, chief executive of Brook, the sexual health charity for young people, said: "Many people still find it very difficult to talk openly about sex and relationships, and often rely on alcohol to help them deal with emotional issues.
"As a result, many young people learn to view alcohol or other drugs as an essential part of the relationship mix.
"Many say they had sex for the first time because they were drunk, and research carried out by Brook in Blackburn found that 67% of young people said they were more likely to have unprotected sex when they were drunk.
"Overcoming our cultural reticence about sex and relationships is a big challenge for this society.
"We need to be open with young people and help them develop communication and negotiation skills to build healthy relationships where they don't need to use alcohol to be intimate."