Ambiguous genitalia

What it means

A genital phenotype that is not clearly assignable to a single gender. Ambiguous genitalia can be evaluated using the Prader scale: Prader 0: Normal female external genitalia. Prader 1: Female external genitalia with clitoromegaly. Prader 2: Clitoromegaly with partial labial fusion forming a funnel-shaped urogenital sinus. Prader 3: Increased phallic enlargement. Complete labioscrotal fusion forming a urogenital sinus with a single opening. Prader 4: Complete scrotal fusion with urogenital opening at the base or on the shaft of the phallus. Prader 5: Normal male external genitalia. The diagnosis of ambiguous genitalia is made for Prader 1-4.

Note that this term can include or combine variations in size and shape, with partial or complete absence of structures. It is preferable to describe the individual components, which are defined below. It is nonetheless a widely used bundled term and as such is retained here. The distinction of this finding from a marked degree of Hypospadias is an example of how this term can be problematic. Genetic gender is determined at fertilization, whereby the presence of a Y chromosome determines male gender. Normally, genetic gender determines gonadal gender which in turn determines phenotypic gender. Testicular development is an active process requiring expression of the primary testis determining gene SRY, which is located on the Y chromosome.

Rare diseases that can present with this66

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions, and Orphanet separately records 2 diseases where this sign is specifically absent. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Also called: Ambiguous external genitalia at birth · Intersex genitalia