Gemma-Rose (7) had a loose front tooth. Every spare moment, she could be found, fingers in her mouth, wiggling and twisting and turning that little tooth. Soon it was hanging by a thread. At lunchtime, two days ago, it finally fell out after one bite of her sandwich, much to my youngest daughter’s delight and relief. She presented it to me on the palm of her hand as if it were a trophy, as if she’d achieved something tremendous. And,…