Size plays a distorting role in the estimation of facial morphology, because it can mask more subtle shape differences. The conventional metric approach provides adequate quantitative information about size only, ignoring the problems of shape definition. Mathematical methods, such as the Fourier series, allow a correct quantitative analysis of shape and its changes. Methods to reconstruct outlines, starting from selected landmarks, and to allow Fourier analysis of these outlines have been developed. These techniques were applied to analyze the age and gender variations in shape of the soft tissue facial contour (frontal plane projection) in a group of 144 healthy children, aged 6 to 7 years and 9 to 10 years. The mean contours differed for both size and shape; Fourier analysis corrected for the size discrepancy and separated the contributions of size and shape to the global morphology. In particular, the sine component (asymmetry) of the soft tissue facial contour was influenced by both age and gender.