The paper investigates the connection between grammatical gender of human nouns and social gender and biological sex of their referents, focusing on the instances of mismatch between them. We analyze data from various languages and conclude that discrepancies between the biological sex of an individual and grammatical gender used in reference to that individual can be accounted for via sociological factors, namely the social roles, status and social behaviours that are considered (in)appropriate in a given society. We propose a pyramid structure, in which grammatical gender is based on social gender, and social gender, in turn, operates in relation to the assumed biological sex of a referent. We show that although there is not always a canonical correspondence between the three levels of the pyramid, there is a hierarchical dependence of the diff erent gender levels upon each other.