What does it mean to dress as a boy or girl?

What does it mean to dress as a boy or girl?

I noticed some people were moaning about boys dressing like girls these days.

But people forget, the fashion has been for men to dress flamboyant in the past.

We have had teddy boys, punks, goths and so on.

In some countries men wear skirts, such as kilts.

To say boys should dress like boys means nothing, as the fashions constantly change.