Everyone has a twin somewhere. I've never seen mine, but I know she's out there.
A friend forwarded this website that does a face recognition scan. You upload a photo and then the site analyzes your face. After this analysis, it compares your facial structure to a celebrity data bank of about 3,200 people. While it seems to analyze just your facial structure, there does seem to be some emphasis on how your hair frames your face and whether or not you are wearing glasses.
I put a recent head shot through the process, and I match with Debra Winger (76%) and Holly Hunter (72%).