Fig. 1 Structural differences in grey matter volume, demonstrated by voxel‐based morphometry. (a and b) Comparison between 45,X Turner syndrome females and normal 46,XX females. Increased grey matter is seen bilaterally in the amygdala and OFC of the Turner syndrome sample. Significance levels were set at P < 0.05, corrected. Local maxima coordinates for amygdala: –37 –12 –24; –34 –6 –25; 21 –10 –24; 33 –6 –24. (c and d) Comparison between 46,XX females and normal 46,XY males. Increased grey matter is seen bilaterally only in the amygdala in the male sample. Significance levels were set at P < 0.05, corrected for whole brain volume in Good et al. (2001a). Local maxima coordinates: –20 –3 –24; –29 –9 –25; 27 –2 –28; 33 –6 –25. The magnitude of effect in our smaller study sample was similar, but the statistical significance was lower. Differences in the amygdalar coordinates partly reflect the different customized templates used for the Turner syndrome and Good et al. (2001a) normal sex difference voxel‐based morphometry analyses.