Anatomic variation of the corpus callosum in persons with gender dysphoria.

Previous postmortem anatomical studies have demonstrated differences between male and female in the size and shape of the splenium of the corpus callosum. The current study using the magnetic resonance imager compares the corpus callosum in 20 transsexuals and 40 controls to determine if the anatomic variance is related to anatomic sex or gender identity. No statistical differences were found in the cross-sectional areas of the entire corpus callosum, regardless of genetic sex or gender. However, the genetic males did have a larger whole-brain cross-sectional area. Also, even though there was a wide range of differences in shape and size in the splenium, the study found no significant differences between the sexes or between transsexual patients of either sex and the controls.