I was the same as a girl, always tomboy, even to point of trying to convince other people I was a boy wearing my "elder sister's" clothes. Its a phase she's going thro, and her parents are neither right nor wrong. My mum made me wear girly clothes and i just resented them even more. My own daughter has been allowed to choose the way she is, and was never forced to wear dresses. She is now the girl my Mother always wanted, which made me feel inadequate. As only a friend, you should just let them get on with it. When she feels ready to be a female, she will, if she wants. If not, she'll carry on as a boy. It doesn't affect any future she may have and therefore she should not be subjected to any form of "change"