Question

An XX individual with congential adrenal hyperplasia (CAH) due to deficiency of 21-hydroxylase (CYP21) will develop: internal genitals from the Mllerian ducts internal genitals from the Wolffian ducts no internal genitals from the Mllerian or Wolffian ducts (urogenital sinus structures only) internal genitals from both the Mllerian AND Wolffian ducts

Answer 1

No internal genitals from the Mullerian or Wolffian ducts (Urogenital sinus structures only).

XX individuals, i.e., females suffering from CAH, the high levels of circulating adrenal androgens prevent the septation of urogenital sinus, thereby preventing the formation of separate vaginal and urethral canals. Further interference leads to clitoral enlargement etc. However, in this case, internal Wolffian structures such as prostrate gland and spermatic ducts are also not virilized since they require higher focal concentrations of testosterone than external genitalia.