“Sex Differences in the Brain Are Not Reduced to Differences in Body Size”, Camille Michèle Williams, Hugo Peyre, Roberto Toro, Franck Ramus2021-11-01 (; similar)⁠:

In their comprehensive review of sex differences in the brain, Eliot et al 2021 conclude that (1) men and women substantially differ in global brain size, but this “mostly parallels the divergence of male/female body size during development” and that (2) “once we account for individual differences in brain size, there is almost no difference in the volume of specific cortical or subcortical structures between men and women”. In sum, almost all brain differences would directly or indirectly follow from differences in body size.

In a recent study that does not have the same limitations as most studies reviewed by Eliot et al 2021, we find that sex differences in total brain volume are not accounted for by sex differences in height and weight, and that once global brain size is taken into account, there remain numerous regional sex differences in both directions (Williams et al 2021a).

[Keywords: sex differences, brain volumes, cortical mean thicknesses, cortical surface areas]

Figure 2: Distribution of the residual effect-size of sex differences across 620 regional brain measures, in a statistical model where log10(regional brain measure) is regressed on log10(total cerebral measure), sex, age, age2, and their interactions, and scanner site. Blue bars reflect the number of regions with a statistically-significant sex difference where the region is larger in males than in females (p < 7.33×10−6). Red bars reflect the number of regions with a statistically-significant sex difference where the region is larger in females than in males. White bars reflect non-statistically-significant differences. Results from Williams et al 2021a.

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Sex Differences in the Brain Are Not Reduced to Differences in Body Size