The controversy about a sexual dimorphism of the human corpus callosum.

A sexual dimorphism of the splenium corporis callosi in man was reported in 1982. The authors described the posterior part of the female corpus callosum to be larger and more bulbous than its male counterpart. From the lateralization research, it has previously been stated that the female brain is less well lateralized for visuospatial functions than the male. The authors postulated that a larger splenium implies a larger number of fibers and that the number of interhemispheric fibers correlates inversely with lateralization of function. However, their sample was very small and not adequately matched for sex. Therefore, we reinvestigated this question. A standardized computer assisted program will be presented. With this program the "classical" parameters have been evaluated and the "rotatory diameter measurement" was performed. No differences between the sexes were seen either for the splenium corporis callosi or for the other parts of the corpus callosum.