Given heterogeneity of the clinical symptoms of intersexuality and vast variation in surgical and medical treatment no evidence-based guidelines are available. The “Network Intersexuality“, funded by the Ministry of Education and Research, will respond to the need for greater scientific knowledge in aetiology and prognosis of the various intersex conditions and the need for better health care. Central element of the network is a large multicentre clinical study. Study design: The study will provide data on short- and long-term outcomes in patients with intersexuality of all age groups. Inclusion criterion is a diagnosis of intersexuality, defined as a discrepancy of chromosomal, gonadal and phenotypical sex. This definition justifies recruitment even when aetiology remains unclear. Each participant shall complete a psychological survey with the support of a psychologist. A medical survey should be filled out by the treating physician to get valid data concerning the physical status. Material and Methods: There is a lack of sensitive and disease specific instruments in the field of intersexuality. We sought to compile a battery of psychometric instruments for different age groups. Extensive literature search and personal communications with experts in the field arised 17 instruments to measure health-related quality of life, mental health, treatment satisfaction, coping, parental impact, social support, body image, gender identity and gender role behaviour. Together with experts and self help groups we developed a parent questionnaire, one for adults and one for adolescents to get specific information concerning the intersex condition. Given the wide variation of diagnosis we sought to develop a medical survey for all diagnosis groups. This questionnaire was developed by a medical German expert group. Discussion: Investigating the impact of risk factors, e.g. type of diagnosis, ambiguity of external genitals, the exposure to prenatal androgens, disease management and disclosure of the condition, will support the development of guidelines for evidence-based medicine in this field.