Disorders of sex development (DSD) include a hetero-geneous group of heritable disorders of sex determination and differentiation. This includes chromosomal aswell as monogenic disorders, which inhibit or changeprimarily genetic or endocrine pathways of normal sex development. However, in many patients affected, nodefinitive cause for the disorder can be found. Therefore,the birth of a child with ambiguous genitalia stillrepresents an enormous challenge. For the structuringof diagnostic procedures, decision making and alsotherapeutic interventions, a highly specialised team of physicians of different subspecialties and experts for psychosocial care is needed to counsel parents andpatients accordingly. This article focuses on the genetic and molecular origins of DSD, the new DSD nomenclature, the consecutive classification, and steps fordiagnosis. Furthermore, we discuss the approach to the family for comprehensive counselling in decisionmaking for their child 

Keywords: Ambiguous genitalia; Chromosome; Congenital heart disease; Pseudohermaphroditism.