Figure 1.

The prenatal development of the external genitalia. From an initially undifferentiated appearance and after an initial primarily genetically driven process, androgenization leads to formation of the phallus and scrotum, and to elongation of the urethra. This requires a differentiated, time-controlled and dose-dependent androgen action as depicted by the different arrows.

Hiort BMC Medicine 2013 11:152   doi:10.1186/1741-7015-11-152
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