Do you hold your pinky up when you hold a glass? Why do you do it?

I was at a restaurant today and noticed a woman holding her drinking glass with her pinky extended. Looking around the room I noticed others. I only saw women do it, no men. I can barely extend my pinky when I’m not holding anything. Trying to do so with a full drinking glass is courting disaster. I can’t see any practical reason for it. Do you?
If you are one of those types, what’s up with holding the pinky up?