In the rapidly expanding research and clinical field of disorders of sex development (DSD), this publication is dedicated to the methodological assessment of DSD based on extensive review of the development of laboratory investigations. Starting with reports on the role of copy number variants, testicular protein hormones and the traditional hCG test in the assessment of DSD, the publication goes on to cover the 'hot' topic which is the reference values for gonadal and adrenal hormones from birth to adulthood. The imaging techniques, endoscopy, laparoscopy as well as the pathology of the germ cell cancer, including the 'genvironment' hypothesis, are elaborated. Considering the increasing importance of the holistic care of individuals with DSD, the publication provides guidance for psychological evaluation in the field, and gives a thorough overview of the opportunities offered by the recent European Reference Network for Rare Endocrine Disorders (Endo-ERN) to ensure equal access to high quality care for all those affected by DSD. The publication concludes with a discussion on the transposition of advanced research knowledge in daily practice on the basis of the EuroDSD network. This publication will be essential reading for all clinicians who are involved in delivering health care to patients with a DSD as well as for scientists involved in biomedical research related to DSD. von Bertelloni, S. und Schmid, M.