(BBC) — My son has just turned 13 and I made him a card to mark the moment he became a teenager. I put a picture of him as a choir-boy next to a Photoshopped shot of him as a saggy-trousered gangsta rapper – the innocent child mutating into a growling ball of rebellious fury. But a series of recent official statistics are making me question whether the old joke is true any more. Teenage...
