MY teenagers tell me everything.
I know that sounds naïve. And I know that it flies in the face of all the evidence about parents not knowing the half of what their children get up to.

And I accept that it’s not normal for parents and their teens to have such an open and candid relationship. And trust me, half of the time I really wish that I didn’t know in quite such graphic detail about all my daughters’ teenage kicks.
But that doesn’t take away from the fact that they do, tell me – even sometimes while I’m walking in the opposite direction, waving them away and shouting that I’d rather not hear.

OK, it’s true that they don’t tell me everything straight away. There are times when they spend a few weeks or months getting comfortable with some new growing-up stage themselves before they feel confident enough to share (sometimes they like to choose a particular moment for its greatest shock value: over the dinner table when we have friends and family round is a special favourite).

And then there was the year when my eldest daughter pretended that she had quit smoking, which she hadn’t. But now she says that was just to keep the peace because she couldn’t bear all the rowing it caused.

As you can imagine I was fascinated this week by the results of a new ICM poll which asked children about all their bad habits.
Are they taking drugs? Having sex? Having unprotected sex? Shoplifting? Looking at internet porn?

It didn’t surprise me that the children were open and honest in their replies.
But the survey went on to question a parent of each child, to find out how much they knew about their 11 to 16 year old’s behaviour.
And that was what shocked me. The parents really were living in cloud cuckoo land.

Of the children who had taken drugs, 65 per cent of their parents believe they haven’t. Of the smokers, 52 per cent of parents didn’t know. Of the children who had lost their virginity, 50 per cent of parents were unaware.
The parents quite literally didn’t know the half of it.

Now I hope this doesn’t make me sound smug. I’m not claiming in any way that being in the know makes me a better mother.
It usually just makes me terrified. There are times when I am filled with admiration at my children’s bravery – and other times when I am shocked to my roots by their naivety.

I know the saying is that a mother’s place is in the wrong. And as a single mum I am constantly worried about my seeming inability to set firm boundaries.
When I was writing this I asked them whether they are frightened of telling me the truth. Or ever frightened of me? They snorted with laughter: “Hell No!”
I am still not sure whether I am supposed to take this as a compliment.

My kids’ theory is that teenagers mainly lie to keep the peace. My two say they tell me because they know I can handle it.
I know that was true for me.
Despite my Catholic childhood, I never thought I was doing anything sinful by lying as a teenager. I really felt that I was protecting my parents from something that needn’t concern them.

A psychologist explained to me (and excuse me if I’ve got the science of this slightly skew whiff) about how part of a child’s frontal lobe actually goes through a period of deconstruction and reconstruction during adolescence. And the result of this is that for a while they really do lose the ability to understand the laws of cause and effect. In other words, children are far more sensible between the ages of seven and 12 than they are between 13 and 20.

It doesn’t matter what mum and dad say. It doesn’t matter what teachers say. It doesn’t matter how punchy and hard-hitting the Government safety slogans and anti-everything campaigns are.
As far as teenagers are concerned, none of those bad things are going to happen to them.

And as a parent, you can talk ‘til you’re blue in the face. You can ground them. You can stay awake all night and drive around town at midnight in your PJs and wellies screaming at them not to hang up again on their mobile, but if they decide they are going to do something, in my experience there is very little you can do to stop them.

Now what I think would be a far more fascinating poll would be to ask parents to tick answers in the same boxes about their experiences of sex, drugs and all that stuff. And, for those of us not too old to remember, what age we were when we first indulged.
It would be fascinating to see the similarities and differences between the generations.
Surely most of us were just as stupid, and all did things we are lucky enough to have lived to regret.

It never fails to amuse me that my children make huge assumptions about what I have ever done or not done. Basically they think I am as pure and unsullied as the virgin snow (people who know me will be falling about laughing now).
I don’t think I’ve ever actually told them lies, it’s just that they’ve never asked the direct questions.

I suppose that, like me, they really would rather not know. Children physically shrink whenever they come face to face with the reality of the fact that their parents have sex.
I know that when I got pregnant the last time, one of my older two realised with a shock that that meant that everybody would know I had been having sex. With her father!

So while I am happy to accept that parents lie to their children, and teenagers lie to their parents, I am just not happy to accept that my teenagers lie to me.
And, by the by, while I was trying to carry out my limited “research” for this column, my daughters couldn’t see how any of this could possibly be worth writing about.

Instead, I was told I should be writing about Britney going off the rails.
Or, more interesting still, about how you can now see pictures of Harry Potter’s willy on the internet (he’s currently starring in/ rehearsing for his role in Peter Schafer’s play Equus: “You used to be able to see his chest and bum,” I was told, “but now you can see his willy too.” Stupidly I asked what it looked like (it’s that boundary business again, I know I’m not good with it). And typically, she told me. I won’t tell you what she said. It was not at all derogatory, but it did make me laugh!