The brains of all vertebrates display gender-related differences. In songbirds, for example, the size of the brain areas that control their singing behaviour could be linked to the size of their song repertoires. In many songbird species, only the males sing and indeed, they do have larger song control areas in the brain than females. However, even species where both sexes sing identically, display the same sex differences in their brain structure. Researchers in Germany have now demonstrated for the first time in the white-browed sparrow weaver, an African songbird, that the extent of these sex differences in the brain varies according to social status, and cannot be explained by singing behaviour as previously thought.