Conclusions derived from face mirroring, however, have been called into question, because it has been shown that mirroring face-halves creates artificial features. For example, if the nose of an individual is slightly bent to the right side, then mirroring the right side of the face will lead to an over-sized nose, while mirroring the left side will lead to an unnaturally small nose. Attractiveness
Facial symmetry has been found to increase ratings of attractiveness in human faces. More symmetrical faces are perceived as more attractive in both males and females, although facial symmetry plays a larger role in judgments of attractiveness concerning female faces.While studies employing the composite faces produced results that indicate that more symmetrical faces are perceived as more attractive, studies applying the face-half mirroring technique have indicated that humans prefer slight asymmetry. Also, studies have shown that nearly symmetrical faces are considered highly attractive as compared to asymmetrical ones. The symmetry of the nose seems to be more important than that of the lips. Dynamic asymmetries
Highly conspicuous directional asymmetries can be temporary ones. For example, during speech, most people (76%) tend to express greater amplitude of movement on the right side of their mouth. This is most likely caused by the uneven strengths of contralateral neural connections between the left hemisphere of the brain (linguistic localization) and the right side of the face. Facial averageness vs. symmetry
Experiments suggest that symmetry and averageness make independent contributions to attractiveness. Aging
Facial symmetry is also a valid marker of cognitive aging.
Sexual selection can only influence features that potential mates can perceive, such as smell, audition (e.g. song) and vision. Such features might be reliable indicators of hidden fitness parameters such as a good immune system or developmental stability. It has been argued that more symmetric faces are preferred because symmetry might be a reliable sign of such hidden fitness parameters. However it is possible that high facial symmetry in an individual is not due to their superior genetics but due to a lack of exposure to stressors during development.It has been found that more symmetrical faces are rated as healthier than less symmetrical faces. Indeed, facial symmetry was found to be positively associated with the perceived healthiness of the facial skin. Also, facial asymmetry was found to be correlated with physiological, psychological and emotional distress.Some evidence suggests that face preferences in adults might be correlated to infections in childhood. See also
Beauty
Symmetry in nature
Patterns in nature
Physical attractiveness

References
External links
FaceResearch – Online studies on facial symmetry by researchers affiliated with University of Aberdeen (Scotland) School of Psychology, and University of St. Andrews (Scotland). "A facial symmetry plugin for the GIMP"—Try experimenting with facial symmetry, using open source software. "Psychological Image Collection at Stirling (PICS) Free Database of pictures of faces
"FaceBase An interdisciplinary research consortium for facial symmetry
"Tübinger Face Database An open research database of 200 merged 3-D faces
"A facial symmetry app for iPhone Experiment with facial symmetry, using a free iPhone app.