5-alpha-reductase deficiency (5 ARD)

5 ARD is a genetic blip that blocks the conversion of testosterone to dihydrotestosterone (DHT) in a growing foetus. DHT is required for the penis and testicles to develop in a male foetus, resulting in ambiguous genitalia. People with 5 ARD may be brought up as girls or boys.

Understanding clitoromegaly, the enlarged clitoris

Large clitorises can develop for several reasons, with the most common being an excess of androgens for some reason when a foetus was developing.