The Role of Fetal Testosterone in the Development of the “Essential Difference” Between the Sexes: Some Essential Issues

2 Introduction The Empathizing/Systemizing (E/S) hypothesis developed by Baron-Cohen and colleagues has two main goals: first, to explain the presence of brain, cognitive, and behavioral differences between the sexes; and second, to explain the pattern of symptoms associated with autistic syndromes. These two goals are connected, since Baron-Cohen argues that autism is the expression of an " extreme male brain " (e.g. Baron-Cohen 2002). Briefly, the E/S hypothesis proposes that levels of fetal testosterone (fT) influence brain development in such a way that lower levels of fT (more common in females) result in a 'female brain' that is " predominantly hard-wired for empathy " (Baron-Cohen 2003: 1). Empathizing is defined as " the drive to identify another's mental states and to respond to these with an appropriate emotion, in order to predict and to respond to the behavior of another person " (Baron-Cohen, Knickmeyer, and Belmonte 2005: 820). By contrast, higher levels of fT (more common in males) result in a 'male brain' that is " predominantly hard-wired for understanding and building systems " (Baron-Cohen 2003: 1). Systemizing is defined as " the drive to analyze a system in terms of the rules that govern the system, in order 2 to predict the behavior of the system " (Baron-Cohen, Knickmeyer, and Belmonte 2005: 820). The " extreme male brain " of autism thus manifests as poor empathizing abilities twinned with superior systemizing abilities. The social and political implications of the E/S hypothesis are readily apparent. While Baron-Cohen (e.g. Baron-Cohen 2003) is clear that a person of one sex may have the brain of the other (thus a woman may have a 'male' brain, and vice versa), on average the sexes will differ in their hardwired cognitive predispositions. This implies that gender inequalities are not due solely to gender discrimination or socialization, but at least partially to an " essential difference " (Baron-Cohen 2003), on average, between the sexes. (For an explicit argument of this kind with respect to sex ratios in math and physics, see Baron-Cohen 2007: 169.) Indeed, Baron-Cohen (2003: 185) argues that individuals with a 'female brain' are biologically predisposed toward occupations that, currently at least, are performed mostly by women, and thus " make the most wonderful counsellors, primary-school teachers, nurses, carers, therapists, social workers, mediators, group facilitators or personnel staff. " By contrast, those with a 'male brain' supposedly enjoy a hardwired facility for traditionally male …