Well, I've had this urge to tell everypony my birthmark for awhile now......So here they are!
I have a patch of moles in the shape of the big dipper on my left forearm. Had it for awhile now.
I also have a patch of silver hair on th right side of my head that is myseriously staying that way, even if I get a haircut, It still grows back.
What's your birthmark?