Prof. Joel studies questions related to brain, sex and gender, applying various analytical methods to analyze diverse datasets, from large collections of brain scans to information obtained with self-report questionnaires. In a series of papers, she has described and tested the ‘mosaic’ hypothesis – the claim that sex differences in the brain do not add-up consistently in individuals; rather, most brains are composed of both features more common in females and features more common in males. Other studies focused on the perception of gender identity and its relation to sexuality. Ongoing studies attempt to characterize the relations between sex and brain structure and function.