I'm lucky in that my girls never really worried about appearance much at that age. Recently my eldest (now 17) has started taking an interest in her appearance and she did get a bit upset about her stretch marks one day when someone (trying to be nice) congratulated her on her weight loss. She's always been skinny, her stretch marks are because she developed so quickly.

We had a chat about the fact that most people don't judge on these things and often don't even notice them. I asked her if she would judge someone on it if she saw them. Shortly after she saw a young woman in shorts with stretch marks who she thought looked great and it helped her to be less bothered by her own.

The only thing my youngest (nearly 15) has expressed about her body is a wish to be shorter because it would make her gymnastics easier! I asked if she was bothered about her height normally and she wasn't.

I wonder if this is just the first time your daughter has had more of an awareness of gender differences and is now wondering if it will be a problem not obviously appearing to be the gender she is. If this comment has come from someone her age, were they taught a cliche of how genders should be? Ie. girls wear skirts boys wear trousers. Hopefully this is just a fleeting concern which will pass once she's mulled and talked it over.