I've been on a couple trips where I was the only guy. Mountaineers snow camping trip: myself and three women in a snowcave, paired up with four women in an adjacent snowcave. Prusik W Ridge with two women. Etc.
As the only guy, I can feel weird/left-out at times when the rest of them are talking about girly stuff. I think it's far more common for a woman to be alone on a climb with guys, and of course guys talk about guys stuff. For this social reason, I can understand why women like to go climbing with each other.... maybe not strictly an all women's trip, but definitely have a few along.
One of my partners lamented to me once while we were sport climbing, something to the effect of, "This is the reason why I like to climb with other women: That guy on that route over there has a really hot ass. I can tell it to you, but you won't appreciate it. With other women around, we can all relish it."
I never hesitate to share