X and Y chromosomes.Differences (or disorders) of sex development (DSD) describes a group of conditions that occur early in pregnancy in which sex development is not typical. Some people may use different words to describe this, such as intersex, or use the name of the actual condition.

There are two main factors that decide whether a baby develops as male or female: genetic factors and sex hormones. The reproductive body parts may develop differently if there is a change in any of the factors needed for sex development. This results in DSD.