Background: Considerable progress has been made  on genetic mechanisms involved in disorders of sex development and on tumor formation in dysgenetic gonads. Clinical and psychological outcome of patients are, as far as evaluated, unsatisfactory at present. Guidelines are emerging in order to optimize long-term outcome in the future.

Data sources: The information obtained in this review is based on recent original publications and on the experience of our multidisciplinary clinical and research group.

Results: This review offers an update on our knowledge concerning gene mutations involving in disorders of sex development, on the renewed nomenclature and classification system, and on the mechanisms of tumor development in patients.

Conclusions: The consensus meeting on disorders of sex development has renewed our interest in clinical studies and long-term outcome of patients. Psychological research emphasizes the importance to consider male gender identity wherever possible in cases of severe undervirilization. Patient advocacy groups demand a more conservative approach regarding gonadectomy. Medical doctors, scientists and governmental instances are increasingly interested in the set-up of international research collaborations. As a consequence, it is expected that new guidelines for the optimal care of patients will be proposed in the coming years.