At the moment, the fashion is for short skirts, and it's something St Aidan's CE High School, in Harrogate, is taking a dim view of, so much so that it has banned skirts altogether for the 15s and under, saying that they are a "risk" for this age group and they now have to wear trousers instead.
I can almost hear the collective teen wail from a mile way. I live in Harrogate and, yes, I do smile at the skirts of the St Aidan's girls, and of the girls at most schools in the area (as for the boys' dropped-waist pants, these are hysterical, but that's another story). In general, though, the girls seem to wear demure opaque tights and are certainly not showing their pants (they leave that to the boys).
Now the St Aidan's girls have started a Save Our Skirts campaign on Facebook, and who can blame them? Have you seen the woeful state of girls' school trousers? They are vile – an affront to decent dressing, often made in a sticky, stretchy fabric that soon looks saggy, baggy and downright slovenly.
At all schools, the girls in above-the-knee skirts and opaque tights look far smarter than those in shapeless trousers.
What next? Many schools already have a make-up ban, with teachers waiting round every corner with face wipes. I went to a parents' evening where one (male) teacher expressed his opinion that girls should be kept "fresh-faced for as long as possible", leading me to suspect he had a problem with not just the under-15s putting "muck" on their face.
What message is all this sending to our girls? That they don't deserve to be taken seriously if they wear make-up? That their intelligence and integrity are linked directly to their hemline?
Make-up and fashion are highly enjoyable interests for many teenage girls, and, compared to drugs, drinking, smoking and fighting, they are pretty harmless ones.
St Aidan's says the girls are "at risk" in short skirts. At risk of what, exactly? If there are men going around Harrogate harassing teenage girls in short skirts, then that is a matter for the police.
If the worry is that boys at school might feel encouraged to behave inappropriately, then it's a perfect opportunity to show them that women are allowed to dress exactly as they choose and that appearance is not a reason to disrespect them or make judgments about them.
And that's a lesson that some teachers still need to learn, too.