"Peer-led" sex lessons have not prevented teenagers having unprotected under-age sex, according to researchers.
In a study carried out by University College London and the Institute of Education, students aged 16 and 17 gave lessons to 13 and 14 year olds in English schools.
It was thought safe sex messages would carry more weight coming from people younger pupils could relate to.
However, while fewer girls went on to have sex before they were 16, there was no effect on the boys' behaviour.
Meanwhile research carried by Sheffield's Royal Hallamshire Hospital has found that young holidaymakers' risky sexual behaviour is fuelling a rise in sexually transmitted infections.
How can teenagers and young people be encouraged to practice safer sex? Why does Britain still have so many teenage pregnancies? What would you do? Send us your comments.
Thid debate has now closed. Thank you for your comments.
I think the way younger children are brought up these days has been a major factor. They tend to be kept indoors, both discouraged from reasonable risk-taking and exposed to a culture of sex, sex, sex in the media. They tend to either have their lives micromanaged, being sent to countless 'safe and supervised' activity clubs or their parents just don't care, letting them watch endless TV. It doesn't surprise me that teens take stupid risks with sex when they are so badly prepared for the passing of puberty.
Darren, Manchester, UK
Once upon a time pregnant pop-stars and celebrities were rarely seen in public once they started to show and neither did they parade their children for the press. Now they are in your face the whole time displaying their bumps and babies like fashion accessories. I do wonder whether that encourages young girls to think that being pregnant is somehow cool, or at least not something to be avoided at all costs.
Jane, Wales, UK
You just need to look at the media for one major cause of the problem. Sex and nudity is used to advertise just about everything. Children's programmes for teens are obsessed with getting a boy/girlfriend. In every other programme, when a boy and girl become friends the FIRST thing they do is go to bed.
I think this topic has to become more open and discussed by many more people in society - not just teenagers and what they probably see as well meaning but patronising adults. I think we have make to sex a less taboo subject and greatly improve access to sexual health services
Phill, Manchester, UK
I'm 20 and more than half of my classmates from school now have children, most of them to secure council property and benefits, and because they live in areas where teen pregnancies are accepted as the norm. If it's socially acceptable for young people to have children while they are still children themselves then it will happen. Parents need to stress the importance of contraception, not give the impression its ok to have a baby underage and not to worry because the state will pay for it.
There's been a concerted attempt in recent years to help (rather than stigmatise) young people who encounter problems with diseases and unwanted pregnancies. As a consequence, other youngsters who may otherwise have been happy to wait until later are given the impression that under-age sex is just normal and everyone is doing it anyway.
Al, Sheffield, UK
I think society swings - and I don't mean we are all swingers! I mean it shifts between permissiveness and temperance. At the moment western society is decadent, and will, in my opinion eventually implode, as did the decadent Roman Empire. There's no point trying to tell teenagers how to behave when the moral compass of the whole of society is swinging towards hedonism. Just turn on your TV and look at 'Big Brother' for an example of how to behave.
The current crises has arisen due to the paradox of sex being taboo to speak about openly, whilst at the same time being bombarded with it in many contexts in the media (the taboo being the bad element in the equation). Show kids the physical effects of STIs in graphic detail - showing how damaging something contracted 'unseen' can be to the body that could be prevented. Much of it is fuelled by virtue of their age and subsequent mentality of invincibility and invulnerability.
Matt, Chelmsford, UK
Stop throwing money at the situation. Some teens are getting pregnant safe is the knowledge they will get council houses and benefits. If they want to reduce this trend, then stop making it so attractive.
Kate, West Midlands
Sex is so much a part of our culture these days. It is featured on every kind of TV programme except those for the very youngest and used to sell every kind of product that it's hardly surprising when hormone-charged teens think they must be missing out on something if they're not 'at it' too. It's wonderful that sex is no longer seen as shameful, but somehow we need to get the message across that it's so much more rewarding when it's part of a deep long-lasting relationship.
Sarah Allen, Somerset, UK
To prevent teenage pregnancy the contraceptive implant should be used as soon as a girl reaches puberty and only removed when she has reached a responsible age. Of course she would still have to take appropriate steps to avoid sexually transmitted diseases, but at least it would solve part of the problem and allow her to get a decent start in life with a job etc, before getting stuck in the rut that many single parent mothers find themselves in before they reach the age of 20.
Gail Beagley, Camberley, Surrey, UK
There's no good reason why we can't provide condom vending machines in all schools. The argument that this would only encourage them is wearing a bit thin. Combine this with decent sex education that goes into all the details in an open and graphic way. This must include detailed descriptions of all STDs, their causes and symptoms, and the consequences of unwanted pregnancies. It's our uptight attitude towards sex and bodily functions that has got us into this mess.
Lloyd Evans, Brighton, UK