It's true

Gimli: It's true you don't see many dwarf women. And in fact, they are so alike in voice and appearance, that they are often mistaken for dwarf men.
Aragorn: [whispering] It's the beards.
Gimli: And this in turn has given rise to the belief that there are no dwarf women, and that dwarves just spring out of holes in the ground!
[Eowyn laughs]
Gimli: Which is, of course, ridiculous.

~Gimli and Aragorn, Lord of the Rings