Errol you might want to take issue with fraggling then who said
Incidentally, wearing a very short skirt gives total freedom of movement, way more than trousers or shorts).
So, given that they give total freedom of movement, way more than trousers or shorts why aren't they worn in yoga classes where what you need is total freedom of movement?
Because, obviously yoga pants give total freedom of movement plus you don't moon the person behind you.
Just had a quick look at m and s size guide for school uniform.
Girls age 15 -16
Height 65 and a half - 66 inches
Waist 28 - 29
Hips 37 and 3 quarters - 39 and a half
Boys 15 -16
Height 67 - 69 and a quarter
Waist 28 and a half - 34 inches depending on fit.
So quite big differences in sizes based on sex.