Evidence from historic post-mortem studies to recent meta-analyses indicate that the brain is structurally, metabolically, and functionally sexually dimorphic (Sacher et al. 2013). In adults, men have larger brains and volumes of gray and white matter than women (Peters 1991; Passe et al. 1997; Good et al. 2001; Luders et al. 2005), while women have greater gray matter-to-white matter ratios than men (R. C. Gur et al. 1991; Nopoulos et al. 2000; J. M. Goldstein et al. 2001; Allen et al. 2003; Luders et al. 2005; X. Chen et al. 2007). The size of white matter structures, such as the corpus callosum, differs by gender although controversies existed since the first description (Oppenheim et al. 1987; Holloway et al. 1993; Bishop and Wahlsten 1997; Dorion et al. 2001). Brain activation patterns show gender differences during a variety of cognitive tasks (R. E. Gur and Gur 1990; R. C. Gur et al. 1995; R. C. Gur et al. 2000; Speck et al. 2000; Weiss et al. 2003; Bell et al. 2006). However, sexual dimorphism of brain measurements in adults can be
