Castration, gelding, neutering, orchiectomy or orchidectomy is any action, surgical or otherwise, by which a male loses the use of his testes. This causes sterilization, i.e. prevents them from reproducing; it also prevents the production of certain hormones such as testosterone.

The term "castration" is sometimes also used to refer to the removal of the ovaries in the female, otherwise known as an oophorectomy or, in animals, spaying.

Castration in humans has been proposed, and sometimes used, as a method of birth control in certain poorer regions.


Surgical removal of a testicle is done in the case of testicular cancer. Surgical removal of both testicles or chemical castration may be carried out in the case of prostate cancer, as hormone treatment to slow down the cancer.

Medical consequences

A subject of castration who is castrated before the onset of puberty will retain their high voice, slight build and small genitals, won't develop pubic hair, and will have a small or no sex drive.

Castrations after the onset of puberty will typically reduce the sex drive considerably, or eliminate it altogether. Castrates can however still have erections, orgasms and ejaculations. The voice will normally not change. Some castrates report mood changes, such as depression or a more serene outlook on life. Body strength and muscle mass can decrease somewhat. Body hair may or may not decrease.

Generally speaking, the effects of a chemical castration (where the action of male hormones is countered by drugs) are more severe than the effects of surgical castration because about 10 percent of a male's testosterone is produced by the adrenal glands (near the kidneys) and not by the testes. Therefore, a chemical castration effectively removes all testosterone in a subject while physical castration results in a ninety percent reduction, but not a total lack of testosterone in the body.

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