What does 'female double' mean in novel?

Question:

What does 'female double' mean in novel?

Hi guys
I've got to write an essay about 'function of female double' on italian short stories (Matilde Serao, Grazia Deledda etc).
and I don't understand what is exactly female double is!!!

Plz help!!

Best Answer - Chosen by Asker:

Female trouble is an expression used to describe a woman's monthly period, and the pain and cramping that goes with it. It also refers to other conditions affecting a woman's reproductive organs, for example cancers. Best wishes. Be glad you don't have to be concerned with it.