Feminism is the stance that sex does not determine gender.
I don't see the need to complicate it further... once the basic premise that a person's genitals don't lock them into a set role in life is established, the rest pretty much falls into place.
As for NOW, they piss me off. Ever since they and GLAAD went on the Eminem censorship kick.
"Good evening. I'm playing the role of Jesus; a man once portrayed on the big screen by Jeffery Hunter. You may remember him as the actor who was replaced by William Shatner on Star Trek. Apparently Mr. Hunter was good enough to die for our sins, but not quite up to the task of seducing green women."
-Stewie Griffin