The BBC website carries a number of stories about girl violence, and the increase that has happened in the last couple of years.
I know I am probably a one track singer, but schools can take the blame for a lot of the changes in our culture. One of the researchers who is quoted by the BBC says that the peer group has a lot to do with it. It's only since we have had schools that there ha been such a thing as a peer group, really. Once upon a time it was what our community and our family did that we modelled in our behaviour, and now it is the peer group that we learn from and want to please.
The Govenment changes to schooling have not had the effect that they wished, of increasing the educational standards of the children who move through state schools. It has had a lot of unintended effects, from a increase in depression and suicide, an increasing number of exclusions and expellings, and an increase in the level of crime and disorder among both girls and boys.
If you look at schooling... REALLY look at it with a fresh mind as though you have been dropped on the planet by Alien Spaceship... you see a lot of dysfunctional social interaction which is ignored by the system. My son was bullied from the age of five until he left school at nine to be home educated. For a while I had to go into the school to put some cream on my other son's arm at breaktime, and I was horrified by the level of violence and bullying that I could see before my eyes on the playground.
There were two teachers, chatting away in the middle of a sea of children, but they seemed oblivious to the mayhem around them. They didn't interfere with children who were abusing each other unless there was blood or a child came to them directly. They were blind to it.
It doesn't surprise me in the least that girls are becoming more violent. It doesnt seem to me that schools particularly value caring and considerate children any more than other teenagers. If a child helps another at school that's labelled as cheating. Schools don't teach children to consider other people's feelings... in general they aren't terribly good at considering other people's feelings themselves...at all.
I'm waiting for the powers-that-be to declare the SATs and National Curriculum a failure and to move onto plan B. One can only hope that one day they might turn to the free and democratic schools to see what they do right, and maybe eve to home educators.