I disagree with that phrase. She's only going to 'be it' if she was already born 'it' to begin with or if she really, really, really wants to be it. And I mean like...come hell or high water, she's gonna be it. Because you gotta practically ruin some lives to get some of the jobs around here, let me tell you. If you don't have the drive for it, you aren't going to get it.
If your son or daughter wants to be something when they grow up that they picked up from television and you don't agree with it, you can't just say no, but you can't say yes, either. You have to handle the issue with care and hope for the best. Otherwise, you might not have a son or daughter anymore.
Really? Media has a huge influence on peoples' values. Kids especially are trying to learn their role in the world through observation, and there really aren't many female characters out there that are fleshed out beyond "girlfriend" "love interest" "mother" "sister" or "sex object". That goes for grown-up entertainment as well, maybe moreso.