Introduction

Disorders of sex development (DSD) are defined as ‘congenital conditions in which development of chromosomal, gonadal or anatomical sex is atypical’. DSD therefore represent a diverse range of conditions that can present at different ages and to a range of different healthcare professionals. Typically, a baby born with ambiguous genitalia will be referred to a paediatric endocrinologist or urologist but DSD can also present in adolescence to gynaecologists because of primary amenorrhoea in a girl, or even in adulthood to fertility services because of difficulty having children. Furthermore, an increasing number of individuals with DSD are being diagnosed in fetal medicine units following a discordance between prenatal karyotyping (performed for another reason) and genital appearance on ultrasound or at birth. An awareness of this range of conditions is thus important for practitioners in many different fields.

Given the diverse and complex nature of DSD, a multidisciplinary team (MDT) approach involving various healthcare professionals with experience and interest in this area is essential (for example, endocrinologist, urologist, gynaecologist, psychologist, geneticist, cytogeneticist, biochemist and ethicist). While this team need not necessarily be involved in every case of apparently ‘simple’ hypospadias if managed by an experienced urologist, an MDT approach is necessary for more complex cases of DSD where there are diagnostic, management and sex assignment issues.

Our knowledge of the causes of DSD, especially at the molecular level, has increased significantly in the past 20 years.