Disorders of sex development (DSDs) are characterized by discordance between phenotypic, gonadal, and genetic sex. DSDs can be classified into three categories based on karyotype: 46,XX, 46,XY, and sex chromosome DSDs. While many of the underlying genetic etiologies of DSDs are known, many remain elusive. DSDs are often diagnosed in the newborn period due to the presence of ambiguous genitalia on physical exam. The expanding use of noninvasive prenatal testing has increased the number of DSDs diagnosed prenatally. Some DSDs are also diagnosed in childhood or adulthood. Working together with a dedicated, multidisciplinary team, the primary care physician can be instrumental in the diagnosis, medical management, and general support of patients with DSDs. This chapter provides background on DSDs and highlights emergent situations and special considerations for individuals with DSDs.