Back in 2005, the first edition of Why Gender Matters broke ground in illuminating the differences between boys and girls�how they perceive the world differently, how they learn differently, how they process emotions and take risks differently. Dr. Sax argued that in failing to recognize these hardwired differences between boys and girls, we ended up reinforcing damaging stereotypes, medicalizing misbehavior, and failing to help kids to reach their full potential. In the intervening decade, the world has changed, with an avalanche of new research which supports, deepens, and expands Dr. Sax's work. This revised and updated edition includes new findings about how boys and girls interact differently with social media and video games; a new discussion of research on gender non-conforming, LGB, and transgender kids, new findings about how girls and boys see differently, hear differently, and even smell differently; and new material about the medicalization of misbehavior.