Historically, essentialist ideas of gender have served both to rationalise and, conversely, to contest social, legal and political inequities. Major strands of first-wave feminism summoned female housekeeping as a metaphor of civic maternalism, invoking traditional notions of women's moral and spiritual superiority over men in the political claim to citizenship. Simone de Beauvoir's mid-twentieth-century disaggregation of biological sex and socially constructed gender, 1 key to second-wave feminism in the 1970s and 1980s, and late twentieth-century postmodernist and queer theory's anti-foundationalist explorations of the performativity of gender, sex and sexuality have been succeeded by a new strain of essentialism in popular culture's mainstreaming of pornography as a central site of female sexual experience and self-definition. At the same time, scientific studies which posit innate differences in mental aptitude as a context for gendered career destinies attract considerably more media attention than work which challenges such findings. 2 If gender essentialism is more likely to have an adverse effect on female than male career progression, a notable exception is the prominent resignation of Lawrence Summers as president of Harvard University following his 2005 pronouncement that the paucity of women in top science and engineering positions was due to the 'unfortunate truth' of women's greater reluctance relative to men to work excessively long hours and their 'different availability of aptitude at the high end'. 3 The subsequent public debate between leading psychologists Steven Pinker and Elizabeth Spelke further underlines the ease with which societal factors -gendered life choices that originate from overarching social and familial structures and socialisation processes -can be claimed as biological evidence of inherent sex traits. There remains, Pinker stressed, a 'reliable average difference [between women and men] in life priorities, in an interest in people versus things, in risk-seeking, in spatial transformations, in mathematical reasoning, and in variability in these traits '. 4 In her riposte Spelke cited numerous experiments pointing to the crucial recognition that the presupposition of gender difference effectuates a 'difference in perception': 'feminine' and 'masculine' traits manifest themselves in the mind of the observer, not the body of the observed. Our gender-inflected expectations shape our interpretation of the ANN HEILMANN