The cause of a chronic urogenital sinus is not known.
Virilization of the female genitalia may cause urogenital sinus. Virilization is when a female develops male features. Males features they could get are:
- Muscle bulk
- Body hair
- Deep voice
Virilization is often a result of a too much androgen (male hormones) in the body. This condition can occur if you have congenital adrenal hyperplasia.