Indifferent stage
This development occurs between gestational weeks 8 and 12.
- 2 mesenchymal cloacal folds form on either side of cloacal membrane
- The 2 cloacal folds fuse infront of the cloacal membrane to form cloacal eminence
- Cloacal eminence enlarges – forms genital tubercle
- Cloacal membrane divides into urogenital membrane and anal membrane
- Cloacal fold divides into genital fold and anal fold
- Another pair of elevation forms on either side of genital fold – genital swelling

In females:
- Genital tubercle – clitoris
- Genital fold – labia minora
- Genital swelling – 2 labia majoras
In males:
- Genital tubercle – elongates to form phallus
- Genital fold – elongates to form urethral groove which forms urethral plate and then urethral canal
- Genital swelling – 2 scrotal swellings, fuse – scrotum
Congenital anomalies:
- Absence of penis/clitoris – no genital tubercle develops
- Small penis – underdeveloped genital tubercle
- large clitoris – overdeveloped genital tubercle
- Divided scrotum – failure of genital swelling to fuse
- False hermaphrodite – gonads are of one sex, external genitalia are of opposite sex