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