Analysis of sexual dimorphism in human face

Human beings can easily distinguish between a male and a female face without much difficulty. The science of recognizing and differentiating different faces by humans is not completely understood and is still under research. Sexual dimorphism is common in humans and indeed in other species of animals as well. Significant differences between males and females exist in many aspects like size, color, body shapes, and weight. In this research, we characterize and analyze the sexual dimorphism in human face as a function of age and of face features. Features are grouped into six categories: head, eyes, orbits, nose, lips, and mouth, and ears. We demonstrate that the face of adult males is significantly different from adult females. We also identify the features that significantly contribute to the dimorphism of the face. This provides a basis for gender-based classification of faces. (C) 2007 Elsevier Inc. All rights reserved.