Joséphine
Much of the book was spent discussing the similarities between males and females and how the brains don't diverge as much as many believe. That biological assessment understandably mattered a great deal. With Men Are from Mars, Women Are from Venus guiding many beliefs about gender, it's definitely important to demonstrate the little scientific merit that message holds.
What was lacking for me was how do we account for the differences? If it's not testosterone (which the author took for granted as debunked), then what are the factors that contribute to the apparent differences based on sex and/or gender? The explanations offered were remarkably brief and didn't entirely answer the questions the book started out with in the preface.