Human lateralization from head to foot: sex-related factors

Sex differences in the pattern and maturation of lateral asymmetries of the human brain have been recently found by a number of investigators, suggesting that sex-related factors may differentially affect the two sides of the body. In this study, asymmetries in the size of the two feet were strongly related to sex and handedness, right-handed males having larger right feet and right-handed females having larger left feet, the reverse being seen in non-right-handed individuals. Since these differences were apparent even in children younger than 6 years, the fetal sex steroids may be critical in governing the maturation of both cerebral and pedal asymmetries.