Why do teenagers take such terrible risks?
'To annoy you,' says my friend Annie.
To be fair, a 13-year-old may not yet realise why it's a bad idea to be walking down a dark alley at closing time on a Saturday night. Youth is eternally optimistic. Boys under 17 (high testosterone; low common sense) are so convinced of their invincibility that hand-to-hand combat under a broken streetlamp sounds like fun.
Recent research from UCL suggests that teenagers like the thrill of risks, especially when they have a lucky escape. So part of the attraction of drinking yourself insensible is that you know, the next morning, that you've survived. Ditto smoking, drugs, dangerous driving and playing Russian roulette with Aids. Nicola Morgan, in her book 'Blame My Brain' raises other possible causes for teenage risk-taking - the brain's frontal cortex not being fully developed; peer pressure; and the fact that we've wrapped them in cotton wool for so long that wild excesses are almost inevitable.
Risk-taking is bad enough. What's worse is finding out about death-defying stunts way after the event. (Don't ever, ever ask your teenage son what he enjoyed most about his gap year in Uganda.)
You can't be completely open about your worst imaginings. It could backfire.
'Text me when you get there,' pleaded my friend Jane when her 15-year-old daughter headed out across London for a party. The text duly arrived - 'At Lucy's.' Some time later, the phone rang - her daughter ringing to check what time she should be back. In the background was the sound of a police siren.
'Where are you?' said Jane.
'At the bus stop,' said her daughter.
'But you texted me to say you were at Lucy's,' said Jane.'
'I know,' said her daughter. 'The bus is late. But I didn't want you to worry.'