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

Abstract

The Empathizing/Systemizing (E/S) hypothesis developed by BaronCohen 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” (BaronCohen, 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 to predict the behavior of the system” (Baron-Cohen, Knickmeyer, and Belmonte 2005: 820).