I'll tell you guys why this can't work most of the time.
Guys can't befriend women because they want to fuck them. It's that simple, once you're past this you can have girl's as "friends".
I've been through this so many times, and everyone I've talked to eventually agrees.
You don't want to fuck your guy friends do you?
"The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents... some day the piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either go mad from the revelation or flee from the light into the peace and safety of a new Dark Age."
-H.P. Lovecraft