Imprinted genes are monoallelically expressed in a parent‐of‐origin‐dependent manner and can affect brain and behavioural phenotypes. The X chromosome is enriched for genes affecting neurodevelopment and is donated asymmetrically to male and female progeny. Hence, X‐linked imprinted genes could potentially influence sexually dimorphic neurobiology. Consequently, investigations into such loci may provide new insights into the biological basis of behavioural differences between the sexes and into why men and women show different vulnerabilities to certain mental disorders. In this review, we summarise (...) recent advances in our knowledge of X‐linked imprinted genes and the brain substrates that they may act upon. In addition, we suggest strategies for identifying novel X‐linked imprinted genes and their downstream effects and discuss evolutionary theories regarding the origin and maintenance of X‐linked imprinting. BioEssays 28:35–44, 2006. © 2005 Wiley Periodicals, Inc. (shrink)

Crespi & Badcock (C&B) provide a novel hypothesis outlining a role for imprinted genes in mediating brain functions underlying social behaviours. The basic premise is that maternally expressed genes are predicted to promote hypermentalistic behaviours, and paternally expressed genes hypomentalistic behaviours. The authors provide a detailed overview of data supporting their ideas, but as we discuss, caution should be applied in interpreting these data.