These words refer to the act of rendering a person or animal incapable of producing offspring. Sterilize is the most general of these, referring to people, animals and even plants, and to any sort of action that makes reproduction impossible: a controversial proposal to sterilize mental defectives; sterilizing fruit flies by radiation treatment; hybrid corn that is detasselled to sterilize it against self-pollination. In reference to people, the word may refer to accidental or deliberate acts and to those bringing about temporary or permanent infertility in either men or women. It may refer also to an occurrence that causes no apparent alteration of the body, as with radiation exposure, or to one in which reproductive organs are modified or removed.

Neuter is rare and no doubt represents an attempt to find a more elegant-sounding term for the deliberate functional curtailing of or removing of reproductive organs from either male or female animals: having both their male and female cats neutered by the veterinarian. Fix and alter are more everyday euphemisms for this word. Spay functions like neuter but is applied exclusively to female animals: a spayed bitch. Geld , similarly, applies to the neutering of male animals: a gelded horse. Sometimes, however, geld can be applied to animals of both sexes, but this wider use is open to misunderstanding.

Castrate can apply both to men or male animals in specifically indicating the removal of testicles. In the case of animals, the word is clearer and more forceful than either neuter or geld : castrating pigs to fatten them for market. Applied to men, the word would now suggest only sadistic punishment or a surgical necessity, as to prevent the spread of a cancer. This was not always so, however: harem guards who were castrated to insure the inviolability of the odalisques; choirboys castrated to preserve their soprano voices. The word recently has become a fad word, echoing psychoanalytic theory, for any symbolic act, especially one performed by a woman, that reduces a man’s feelings of manliness: women who castrate their husbands by humiliating them in public.

In general farming use, the polite castrate is replaced by the earthier term cut : We shall have to cut the lambs next week. Many have replace this with the euphemistic mark : Marking techniques are not so crude as they used to be. Marking , which is carried out on very young sheep, involves not only sterilization but shortening of the tail. Ewe lambs also are said to be marked when their tails are docked in this way. Use of the word mark can lead to confusion because, for some farm animals, it describes a means of identification, as in ear-marking .

Emasculate may apply to male animals but is more commonly restricted solely to men. The word differs from castrate in referring more to the damage than to the actual removal of reproductive organs: emasculated in the war by flying shrapnel. The word is sometimes used euphemistically for castrate . Metaphorically, emasculate refers, like castrate , to any act that reduces a man’s sense of manliness. While less dramatic than castrate in this use, the word would seem to have greater metaphorical felicity, since no physical alteration is necessarily suggested by the word. Nevertheless, the reference to psychoanalytic theory is less apparent and may explain the faddish preference for the stronger term. Emasculate is used also as a generally applicable metaphor for weakening: amendments that emasculated the provisions for enforcing the statute.

Vasectomize and Hysterectomize , the former applying to men, the latter to women, are medical terms for surgical operations that sterilize the person operated on. Actually these terms are more commonly used in their noun forms: vasectomy and hysterectomy. To vasectomize is to perform a simple, duct-tying operation, sometimes reversible, that is chosen specifically to make a man infertile and has no effect on body chemistry. To hysterectomize is to remove the uterus and sometimes the ovaries and Fallopian tubes to stop uncontrollable uterine haemorrhaging, to remove large fibroid tumours or to eradicate a cancerous condition. The operation is never done simply to achieve infertility, since it is on the body’s chemical balance. The Fallopian tubes can be tied, however, in a simply, sometimes reversible operation whose object is the same as that of vasectomy in a male.