"This is a remake of a facial geometric sexual dimorphism diagram from Valenzano, D. R. et al. (2006). The blue
bell curve on the left represents the male faces, and the pink bell curve on the right represents the female faces. The purple area in the center represents the overlap of the two bell curves where the feminine male faces cannot be distinguished from the masculine female faces. The bell curves show that the proportion of female faces that are more feminine than the most feminine male faces is much greater than the proportion of male faces that are more masculine than the most masculine female faces."