
Monorchism

Monorchism (also monorchidism) is the state of having only one testicle within the scrotum.
Causes.
This can be due to:
Monorchism in nonhuman animals.
Although extremely rare, monorchism has been observed to be characteristic of some animal species, notably in beetles.
Terminology.
An individual having monorchism can be referred to as "monorchid".