Monorchism


Monorchism is the state of having only one testicle within the scrotum.

Terminology

An individual having monorchism can be referred to as monorchid.

Causes

This can be due to one testicle:
  • Not descending into the scrotum during normal embryonic or fetal development, also known as undescended testis or cryptorchidism. In this case the testis is within the abdominal cavity, somewhere along the normal route of descent – most commonly, within the inguinal canal. Such a testis has an increased risk of malignancy.
  • Disappearing during development due to some intrauterine insult. This is thought to be most likely vascular, such as testicular torsion.
  • Not being created in the first place, known as congenital monorchism.
  • Being surgically removed through orchiectomy.
  • Being injured.

    Notable cases

Due to testicular cancer

Although extremely rare, monorchism has been observed to be characteristic of some animal species, notably in beetles.