Figure 1: Both twins underwent orthodontic work for cross-bites that were in opposite directions. The molars were tipped and rotated identically. A, B, D: The right-handed twin’s right lateral incisor (red arrow) was larger than her left lateral incisor. A,C,E: The left-handed twin’s left lateral incisor (blue arrow) was larger than her right. G, H: The lower teeth appear to be almost identical.