One of my co-workers once said when she worked as a clerk in a video store she would sometimes get gay couples walk in and she would immediately see which of them was the "woman" and which of them was the "man."

Another co-worker, who knew perfectly well that I have been in at least one same sex relationship, then replied "Oh, it's the same with the lesbians. You can always see which of them is the man."

(If that's not enough for your amusement, one of my colleagues said to another: "Right, you're brother is gay! Can't he help me pick out an outfit?")