The flat belly is the 21st century erogenous zone. Girls are braving the winter chill in jeans that hang below the navel and jackets that barely stop at the midriff.

Every generation has its exposed part. When I was a teenager, we wore skirts three-quarters of the way up our thighs and knee-high socks, prompting my mother to comment that we would all probably suffer arthritis of the knees when we got older.

Style is one thing, enforced style is another. I don't think 10-year-olds should be baring their navels. I find myself unable to find jeans for my two girls that actually reach the waist. The low-slung style is so pervasive that our local school uniform shop has actually stopped stocking trousers for girls, because the girls demanded low-slung hipsters with wide legs that trail the ground. The uniform manufacturer, quite sensibly, wouldn't comply with their wishes.

My girls were delighted to get boys' school trousers that actually touched the waist and jumpers that covered their stomachs. They find it comfortable. I'm just waiting for the day when they give up comfort in favour of being sex objects. I hope it doesn't happen.