I recently visited a secondary school on a non-uniform day. You know the sort of thing: pupils pay a pound for the privilege of leaving their uniform at home and wear casual clothes. It was "casual Friday".
Sports tops, denims and flashy jackets are usually the norm. But in this particular instance, no limits seemed to have been set. It was, for many of the girls, a competition to wear the shortest skirts, the skimpiest tops, the most make-up. It was just awful.
And it wasn't just senior pupils who were competing to look sexy: some of the younger pupils joined in. One pupil, just 12 years old, was dressed and made up to look like a contestant in a Miss Bimbo contest.
But it is not just non-uniform days which are becoming a problem. Some pupils, including 12- and 13-year-olds, now attend school wearing the sort of clothes and make-up which many teachers believe to be entirely inappropriate for places of learning.
Outside of school, the sale of Playboy pencil-cases and "eye candy" gym tops has drawn attention to the sexualisation of young girls for commercial purposes.
Schools, at least, should be drawing a more definite line about what is, and what isn't, acceptable.
Perhaps I am being overly prim and all this dressing up is just harmless fun? But key statistics suggest otherwise: figures for teenage pregnancies, and sexually-transmitted diseases, are at worrying levels and are noticeably higher in this country than in most other European countries.
There are safety issues too. In my friend's school, a pupil in S3 broke her ankle after falling down stairs wearing heels which were much higher than she could deal with.
Young people's thinking on such matters is also a concern. Surveys show that an increasing number of female pupils believe good looks will get them further in life than education or personality. Many teenage girls, it is also reported, would consider having surgery to change their appearance. I recently marked an essay in which the female author, just 13 years old, said her dream was to win a beauty contest.
It is not easy being a teenager and, for girls, there are all sorts of peer and media pressures to look good, get a boyfriend and conform to the prevailing model of what constitutes "coolness" or "hotness".
And if you don't fit the model, then be miserable and maybe even worry about your body shape. Early sexualisation, it is now clear, is linked to eating disorders, low self-esteem and depression among girls.
I have the opportunity to visit various schools and can report that there is great variation in what heads tolerate in terms of dress. As some heads seem to find it harder than others to discourage inappropriate dress, it may be time for more stringent national guidelines on school dress codes.
Perhaps, also, guidance is needed on what schools should be doing to help young people work these things out for themselves. Responsible citizenship, one of the new curriculum's four capacities, should mean more opportunities for pupils to investigate and discuss issues such as the objectification of young women.
And what about telling everyone a bit more about the female pupils who ignore media pressures, set their own boundaries and who would rather join Amnesty International than aspire to be glamour models?
These are the sort of things parents say they want schools to offer, along with stricter policies on school uniform and face make-up. And parents definitely don't want non-uniform days to degenerate into anything approaching a contribution to the sexualisation of young girls.
John Greenlees is a secondary teacher.