The bigger problem in a co-ed school is the reasons behind the clothing choices.
I had to chuckle upon reading that sentence. I did because the thought that came to mind when I read it is that if there is a problem with anyone's -- minors and adults -- sartorial choices, it derives from the reason they made the choices they did. There are far too many reasons and choices to enumerate, but one example that fairly well summarizes the gamut of the reasons is found in the photo-meme below.
Quite simply, a major problem is that folks think they look good wearing "A" when the reality is that their body just isn't a "A-appropriate" body. And let's be honest, why would anyone willfully leave their house not on a stretcher and looking bad, that is to say, looking either like they don't own a mirror or like someone other than they is whom they see upon looking in the mirror?
Aside:
If you like clothes, it behooves you to stay fit because when you are, you won't look bad wearing anything that fits, but when you're obese, that you can fit in the garment doesn't mean it fits you.
-- My wife
My wife delivered that statement in a conversation explaining to our daughter why she, like her brothers, was required to do aerobics and weight training.
As a pre-teen, our daughter wasn't keen on having to hit gym. As a high school senior and now woman, there's no denying she revels in the fact that she heeded the advice her mother gave her. She absolutely loves the fact that she's grown into being "Hollywood hot" woman, as we teasingly refer to her looks and shape. It took a few years of "bitching and moaning" for her to get on board with working out; however, now, she works-out seven days a week. LOL
FWIW, my wife and I had one overarching goal, to raise our kids so that upon becoming adults, the world would, as much as possible, truly be their oyster. While part of that has to do with career and related matters, an equally material part of it rests in the social sphere, which is why we taught/required our kids to get fit and stay that way. Now that they're all grown, whether they maintain that, to what extent, and/or for how many years into the future they do/don't is their choice. As far as I'm concerned, I am content that they "entered the world," so to speak, having no material deficits. I think as a parent that is about all one can reliably do for one's kids.