Disorders of Sexual Development

Disorders of sex development (DSD) are defined as congenital conditions in which development of chromosomal, gonadal, or anatomical sex is atypical. The initial determination of sex by genes directing the bipotential gonad to become an ovary or a testis is called sex determination. The subsequent development of the genital appearance resulting from the function of that gonad is called sex differentiation. Some useful and at times confusing terminologies used over the years need to be clarified for a better understanding of the subject. Chromosomal sex is referred to as the sex based on the number of sex chromosomes. Gonadal sex is the sex according to the gonadal differentiation. Phenotypic sex is the sex based on the external anatomy of the genitalia. Gender identity is the individual’s perception about his/her own gender. In some individuals, gender identity is different from the phenotypic sex. Intersex is a term no longer in use; it has now been replaced by the term DSD. Ambiguous genitalia refers to the appearance of external genitalia that are not easily classified as male or female.