This can be achieved by surgically removing the testicles or by administering hormones and antihormones that shut down testicular function.

Gerres L, Brämswig JH, Schlegel W, et al.: The effects of etoposide on testicular function in boys treated for Hodgkin's disease.

In 1963, University of Washington researchers irradiated the testes of 232 prisoners to determine the effects of radiation on testicular function.

It includes an investigation of the effects of infection, inflammation and immune factors on testicular function.

Androgen replacement therapy is also used for men who have lost their testicular function to disease, cancer, or other causes.

Similarly, stimulation of testicular functions via gonadotropic-like hormones may enlarge their size.

The regimens that threaten ovarian and testicular function are mainly radiation therapy to the pelvic area and some types of chemotherapy.

Men taking estrogen or naturally producing higher levels of the hormone are thought to be at slightly increased risk, as are men with Klinefelter's syndrome, which results in low testicular function.

GnRH analogues are often prescribed to prevent the reactivation of testicular function where surgeons require the cessation of estrogens prior to surgery.