Open Peer Commentary Fitch & Denenberg: Sexual differentiation of the brain
Effect sizes and meta-analysis indicate no sex dimorphism in the human or rodent corpus callosum
Douglas Wahlsten a1andKatherine M. Bishop a1 a1 Department of Psychology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
Sex dimorphism occurs when group means differ by four or
more standard deviations. However, the average size of the corpus
callosum is greater in males by about one standard deviation in
rats, 0.2 standard deviation in humans, and virtually zero in mice.
Furthermore, variations in corpus callosum size are related to brain
size and are not sex specific.