We all know that a woman is an adult human female - just as a mare is an adult equine female, and a ewe is an adult ovine female. 

There is nothing to be gained, and everything to be lost, by trying to change that simple, descriptive, biologically accurate definition.

Let's resist the attempts to re-define "woman" so it doesn't actually mean anything at all.

Are you a woman or a girl? Sign this for yourself. Are you a man or a boy? Sign this for your mother, your grandmother, your wife, your girlfriend, your daughter, your granddaughter, your niece.