There are one or two things I do not understand when it comes to 12-year-old girls. Things like why being asked out by a boy is a deeply humiliating experience requiring you to slam your bedroom door shut and refuse to talk to the rest of the family.
I also don't understand why said boy - as a proof of his ardour - then steals your calculator and smashes it. Nor does it quite make sense to me that his friends call you a "snobby cow" and lob a can of cola in your direction. Finally, what I really don't understand, if this is upsetting you so much, is why on earth you don't tell your teacher.
It's not as if Sarah-Jane goes to the kind of school where thuggery is tolerated or, as it was in my day, actively encouraged. Having your head stuck down the lavatory was virtually core curriculum stuff when I was 12, but at our local comprehensive they get structured classes on sexual harassment and take A-levels in assertiveness.
"Didn't Mr Hipflask say you must report any instances of bullying straight away?" asked Sarah's mother, only to be told in no uncertain terms "Mum!
You don't understand!"
What, in these circumstances, is a parent to do? The idea of one's offspring suffering is anathema. Sarah trained us from Day One to come running the moment she emitted even a whimper so why, when she reaches 12, must I stand mutely by as my daughter slams her bedroom door and weeps into the pillow? "Sarah," I said firmly but kindly to the door, "if you won't tell Mr Hipflask, I will."
I was using my deepest paternal voice. The kind of voice that might reassure a crowd of timid townsfolk yet strike terror into the heart of any gunslinger who fancies his aim with a can of cola. The door opened immediately. "No, Dad! God, you just don't understand."
We were approaching High Noon, so I told my daughter that the current state of affairs could not go on. I wanted to sound sensible, concerned, reliable but most of all strong.
"I'm going down there, Sarah." A man has to do what a man has to do after all.
"Dad," said Sarah. "You can be such a bully." And she slammed the door shut again.
There are indeed some things I do not understand.