ABSTRACT
This chapter focuses on gender-related behavior, a field in which evidence of various prenatal and postnatal influences is rapidly accumulating. One of the roadblocks to progress lies in the interpretation of the data regarding the relative contribution of constitutional vs. environmental or innate vs. learned factors. The model most often applied is the main-effect model, which postulates that one factor determines or predominantly influences a particular behavioral outcome. The outcome of development in a transactional model may consist of many different options, but regarding one aspect of psychosexual differentiation — gender identity development —there are surprisingly few possibilities. Gender identity, as a complex and specifically human phenomenon, may not be the most suitable aspect of gender on which to examine the interaction between biological and psychological variables. Sex-dimorphic behavior, encompassing those aspects of personality, play behavior, and temperament in which boys and girls and subsequently men and women differ, may be a more appropriate focus.
