RIGHT, so here I am, sitting in the car outside school, waiting for Smaller Son to collect his GCSE results. There are other mothers in other cars. They all have the same expression - a sort of fixed semi-smile of optimism, hoping brightly for the best, but preparing a few consoling words for the worst. It looks rather as though they have toffee stuck to their back teeth.

I look in the mirror. I have exactly the same expression.

They never tell you about this in the childcare books, do they? They warn you about sleepless nights and nappy rash and keeping the kettle flex out of the way. But no one tells you that in 16 years time you'll be sitting outside school gates in a panic.

Not that Smaller Son and his friends have panicked. Well, not until last night that is, when they realised that this day was actually going to dawn. Sluggards the lot of the them usually, today they were all up at the crack of dawn. On the way in they talked carefully about football, took bets on how many people would burst into tears - though I'm not sure if that included mothers...

It doesn't help us mothers of sons to read of how girls have outclassed the boys yet again. Parked outside the school gates it's suddenly easy to believe. The boys roll up, a motley crew, shouting across at each other, engaging in mock fights, full of nerves and bravado. Then the girls arrive. They are cool, stylish and sophisticated. They stride out as though the world belongs to them. They look about ten years older than the boys and a lifetime wiser.

I go back to the stuck toffee smile.

This is one of the worst parts of being a parent. Watching your child faced with a challenge and you're helpless to do anything about it. I still have nightmares about Senior Son's first swimming badge. Four years old and he was the only child in the deserted Dolphin Centre pool, doggedly doing his 25m. He looked so little and the deep end looked so deep.

Then there were all the football matches, rugby matches, school concerts. They have long since forgotten the parts they played, while I can still remember every word of their various roles, sitting in the audience, desperately willing them to get through it.

But the whole aim is to make them independent, to think for themselves, cope with anything and, occasionally, accept failure.

Only I hope there's no failure today.

Students are starting to emerge from the school. Girls are clutching their pieces of paper and giggling and gasping. The boys look more non-committal as they walk back to the cars, but close-up you can see that they're beaming.

Some have done brilliantly, many have done well. Most have done what they need to go on to the next step. You can feel the relief in the air. But do they want to share that moment with their mothers? Of course not. They dump the bits of paper in the car as quickly as they can and then go jauntily into town to celebrate.

And that's something else the childcare books don't warn you about.....