Part 1: Considering sex and gender in research studies -- Sex and Gender Science -- Best practices in the study of sex? -- Best practices in the study of Gender Differences -- The special case of a lack of sex differences - the naked mole rat? -- Lateralization and -- Part 2: Sex differences in cognitive and mental health across the lifespan -- Depression -- Schizophrenia -- Immune and neurodevelopmental disorders - autism? -- Social Cognition -- Cognition and cognitive ageing -- Part 3: Diseases of the brain and relevance of sex -- Epilepsy -- Stroke -- AD -- Parkinson's -- Multiple Sclerosis.