I got an email today from the Advertising Standards Authority inviting me to a public debate entitled Too much, too young: Are advertisers sexualising childhood? It's a question that needs to be answered, inside and outside the ad break…

Kids have always been exposed to sexual imagery, although now it seems more commonplace and explicit than before. Our fears lie in the fact that we know that the constant repetition of certain images or scenes creates a benchmark for normal behaviour - and kids do copy what they see…

But as a child, you don't process sexual images the way an adult would. Kids watched Saturday morning Tiswas for the custard pies, fathers watched it for Sally James in a tight t-shirt. Our frame of reference is different and a lot of the sexual images that adults are aware of go over a child's head.

However, children are also drawn to things of a sexual nature. They track them down on parents' book shelves, in bottom draws and in secret stashes of magazines. Perhaps you remember your own childhood curiosity, particularly once puberty kicked in? Children are sexual beings too, even if we don't like it and they don't understand it...

However, it's confusing and potentially frightening if their curiosity is too easily answered by readily available footage of hard-core gang bangs.

Our children live in a sexualised world - that horse has bolted and we can't force the contents of Pandora's box back inside. This means that yes, we should try and limit their access to scenes of an inappropriately sexual nature (who decides what is inappropriate is a separate debate) but we must also give them a context for everything that will inevitably slip - or be pushed - through the net.

They need to be able find a comfortable level of understanding for what they see, separate fact from fiction and get the information they need to make the right choices about their own bodies. 

Because there's no clear, consistent and thorough approach to sex education, there's a randomness about the scraps of knowledge our young people are accumulating.

In one of my research groups earlier this year, a number of the Year 9 group had picked up on a 'fact': women are extra horny (sic) three days of the month. That was it. There was no context for this and no sense of when those three days might be. It was a mysterious and somewhat perplexing half truth.

This is the kind of thing that doesn't necessarily get covered in sex ed - one of a thousand little questions that may not even get vocalised - and really, it's not such a difficult question to answer, is it?

Of course, other issues are more complicated. Addressing the fact that most of those 13 and 14 year olds had watched porn on their mobile phones is one example - but you know what? We can't pretend it's not happening.

If we don't step in and give them guidance, support and information, they will be getting their knowledge from pornography, music videos, tabloid newspapers and magazines that seem to have put gender equality on the back burner - and aren't at all reticent when it comes to shouting about their own particular brand of full frontal, objectifying and often misogynistic sex. These voices desperately need a counterbalance.

Our young people should be able to join a dialogue that raises the profile of respect, self-awareness and positive body image. They should be hearing a voice that talks about freedom from stereotypes, freedom of expression and freedom to be physical when you're ready for it, in a way that feels comfortable, safe and exciting. Yes - exciting. Because if you're going to be having sex, shouldn't it be the best sex possible?

We should be encouraging their questions, giving them a forum to learn with honest answers that aren't full of prime time or late night sensationalism and misplaced embarrassment.

How do you really know when you're ready for sex?
What should sex feel like?
How do you become a great lover?
Is my body 'normal'?
Sex hurts. What should I do?

We need to answer those questions - and many more besides.

Parents need advice on how to raise the subject and discuss it with their children. It's not an easy thing to do because when we get into the real nitty gritty of sex, it is all about emotions, beliefs, and very subjective, personal experiences.

Teachers need the support and training that will give them the confidence to provide sex education that ticks all the boxes - something they didn't necessarily sign up for.

And finally, we all need to remember that sex can be the most powerful, unifying, beautiful, passionate, loving experience on the planet - and who's telling our kids that?

Yesterday, I made a promise that I intend to keep: 

"I am committed to creating a space where young people can talk openly and honestly about the sex and relationship issues that matter, offering my full support as a coach and mentor. I pledge to help them develop the confidence, self-awareness and self-respect they need to make the choices that make sense - for them."

And that promise is published on Brook’s Sex:Positive website for the world to see. 

Sex:Positive launched on 12th February. The aim of the campaign is to challenge negative attitudes and create a more open and honest dialogue about young people, sex and relationships. After all, it's hardly fair to vilify teens as immoral, promiscuous risk-takers, but not give them the facts and guidance they need to make better decisions.

Being Sex:Positive means celebrating sexuality and embracing individuality, rather than banging on about STIs and unwanted pregnancies. It means talking about the good stuff.

So what is a celebration of sex?

I think it's probably best summed up by the feelings that the act itself evokes. Pleasure, intimacy, fun, playfulness, love, openness and passion being some of the first that spring to mind...

In one of my teenage research groups recently, I asked whether there were any general questions about sex that still needed to be answered by the time they reached the sixth form. A confident 17 year old told me: 'No - we're fine.' 

Of course, his response probably wasn't representative of the entire group, but I continued: 'OK. Great. So how could sex and relationships be better?' The general response was 'more sessions like this one' - which seemed to me like another reason to celebrate. 

I know that talking and listening are part of what makes sex great. When there is a desire to build on what you already know, to learn more about yourself and your partner, to develop physical eloquence as a sexual human being, sex becomes an expression, not just a statement, a journey not just a destination. 

By offering good sex education that genuinely supports the individual, whatever their sexual orientation, we offer young people the chance to evolve into sexual maturity with confidence.

By teaching them to respect themselves and others and giving them the information they need, we can increase the likelihood that their intimate relationships are a source of happiness and fulfilment rather than confusion, frustration or disconnect.

"If our teachers are embarrassed to talk about sex, what are we supposed to think about it?"

"They focus on the bad stuff… not how good it can be"

"All girls want to be thin with big boobs"

"You need to turn a girl on to give her pleasure"

These were just a few of the opinions that came to light during my research group with twelve 14 year olds earlier this week.

Initially, it felt a little like herding cats. They wandered in and out of the room, nipping to the shop for chocolate, talking and laughing amongst themselves, playing a guitar - but after a while it felt like they were enjoying the session like a relay race, a process of taking it in turns to focus and I always had a generous quota of engaged minds. 

Conversation continued in an unabated ebb and flow for pretty much 90 minutes and their ability to mentally multi-task was both inspiring and energising - when did I get so old and static?? 

My aim was to explore their attitudes to relationships, to find out what they thought about sex education. I also wanted to get a handle on what they needed to help them develop the confidence to make positive choices about their future relationships and sex life. 

By the end, for this group at least, I had a sense of what mattered to them, what they cared about and also how much they are currently in transition, making the move from child to adult - and looking for answers. In the moments when I gave them a few basic facts, the room was silent. They were listening, soaking up knowledge like sponges.

Could they embarrass me? They gave that a go for a while and it didn't work, which they were pleased about. This seemed to be a fundamental issue in their sex education - the people they would look to for guidance weren't confident enough to give them the information they needed. Teachers weren't doing it. Parents were sometimes helpful but the response to their involvement was lukewarm and siblings and peers were only a minor part of the mix. 

So who would they talk to if they had a really big problem, or were worried about something? A few said they'd be happy to go to their doctors, but I was conscious of the gap. 

Of course this was a very small insight into the extremely broad field of sex education, evolving identity and emotional development - but it's given me a valuable starting point for my workshops. And those teenagers enjoyed it too, wanted to do more and gave me 9 out of 10 for my efforts - and whatever age you are, it's always nice to be appreciated.

So watch this space. There'll be much more to come.