ABSTRACT
Male and female adult bodies have several key sexual dimorphic characteristics, as a result of hormonal and genetic influences in utero and during adolescence. In its most general sense, brain sex theory takes as its starting point the assertion that these sexually dimorphic characteristics must also (a) be found in the adult human brains and (b) form the basis for behavioural differences between men and women. In this chapter, the author reviews the evidence for anatomical and functional differences between adult male and female brains and the evidence for behavioural differences between males and females. The author also explores some of the complexities for interpreting brain sex accounts for anatomical and functional differences in the brain, namely, the profound effects of experience on brain structure and function, the complexities of the ways that testosterone influences brain processes (e.g. testosterone is aromatised into oestrogen in the human brain), and the variable standards scientists apply when assessing such sex-based differences. I also explore the kinds of differences in cognition and behaviour which arise from (or are claimed to arise from) such neural differences between the sexes: It is argued that this has been hampered by a narrow view of what, exactly, we aim to account for when we talk about such differences, for example an ongoing debate about the reality of male/female differences in maths ability compared to a complete absence of debate about the origins of male criminal behaviour.
