During some parts of the year, some girls don’t have vaginas.

It used to be believed that all European moles were male through their first year and only then did some become female. This bit of folklore stems from the fact that, outside the breeding period, the female’s vagina is sealed with a layer of skin. Since the female urinates through a structure which closely resembles a male’s penis, it is impossible to sex moles by looking at these parts during certain times of the year.

And some girls have penises all the time.