Sexual dimorphism in foot length proportionate to stature

Background: The preponderance of existing results suggests that, relative to stature, women have smaller feet than men. However, several investigations indicate that the relationship between foot length and stature may be curvilinear, a pattern that, due to the dimorphic nature of stature, would mask the true direction of pedal sexual dimorphism in published results. Aim: The study aimed to determine whether proportionate foot length is sexually dimorphic and, if so, the nature of that dimorphism. Materials and methods: Surveying genetically disparate populations (USA, Turkey, and Native North and Central American), we examined data from three previous anthropometric studies (Davis 1990, Parham et al. 1992, Özaslan et al. 2003) and foot tracings from the Steggerda Collection at the US National Museum of Health and Medicine. Analyses explored sex differences in the ratio between foot length and stature, and tested for nonlinearity. Results: Although varying in degree across populations, proportionate to stature, female foot length is consistently smaller than male foot length. Conclusion: Given the biomechanical challenges posed by pregnancy, smaller female proportionate foot length is somewhat surprising, as foot length affects dorsoventral stability. It is possible that the observed pattern reflects intersexual selection for small female foot size, a cue of youth and nulliparity.