In females, spaying will help prevent most breast cancers, the second most common cancer found in female cats.  Spaying will also help prevent most ovarian and uterine tumors, heat cycles, aggressive behaviors and the desire to stray and roam away from home.  In males, neutering helps prevent spraying, prostate enlargement and cancers, anal and rectal tumors,  aggressive behaviors and the desire to roam and fight which can easily result in deadly, infectious viral diseases such as Feline Immunodeficiency Virus, and Feline Leukemia, both of which are fatal disease for which there are no cures.  The vaccines for FIV and FIP are not recommended by the American Association of Feline Practitioners' Vaccine Protocols and the FeLV vaccine are not 100% effective.  

More than 30 years of clinical research and experience has demonstrated that the ideal age for both procedures is between 8 and 16 weeksBecause of the small amount of abdominal fat and muscle present in young animals, there is substantially less cutting and tissue trauma (the typical incision in a female is only 1 cm) with virtually painless recovery and healing.  Visualization of the ovarian pedicle is also excellent.  This, coupled with the small vessel size, allows for precise hemostasis and virtually no bleeding which significantly shortens operative time. Most animals are up and about within minutes and eating within an hour after surgery.

The safety of early neutering is still questioned by some veterinarians because of their unfamiliarity with surgery and anesthesia on pediatric patients and because of outdated and unfounded myths, most of which have been dispelled by more than 30 years of  controlled clinical studies.

Early-age Spay/Neuter is Endorsed By

AVMA-American Veterinary Medical Assoc
AVAR (Assoc of Vets for Animal Rights)
American Humane Association
The American Animal Hospital Assn
HSUS, Humane Society of the US
Cat Fanciers Association
Texas A & M College of Vet Med,
Univ of Minnesota
Columbus Academy of Veterinary Medicine
Knox County Humane Society
Capital Area Humane Society
Massachusetts Society for the Prevention of Cruelty to Animals 
Doris Day Animal League

The personality of the pet is not altered, but rather, the cat becomes less wild and a more socially acceptable creature.  Allowing a  female have a litter or to allow animals to mate does not improve the animal's personality or health.  Breeding animals are usually less social than spayed/neutered animals.

 Click here for links to articles about early-age neutering.                                

Cancers Preventable by Spaying/Neutering


OVARIAN CYSTADENOMA   cystic tumor, often benign but can grow to a moderate size. Possible cure with ovariohysterectomy. Also preventable by spaying.

EPITHELIAL (i.e., carcinoma),  and sex-cord stromal (i.e., granulosa cell tumor, Sertoli-Leydig cell tumor, thecoma, and luteoma) tumors.   Preventable by spaying

OVARIAN ADENOCARCINOMA:  malignant tumor of the ovary. Can be prevented by spaying female cats.

GERM CELL TUMOR: include dysgerminomas and teratomas, tumors from embryonic-type tissues in the ovaries. Uncommon, can be moderately malignant. Ovariohysterectomy, chemotherapy and radiation will be needed for a cure. Preventable by spaying.

UTERINE LEIOMYOMA: the most common uterine tumor found in female cats. This tumor originates from smooth muscle within the uterus, and is usually benign. Usually no outward symptoms are visable.  Ovariohysterectomy usually produces a comple cure. . Preventable with spaying except in very rare circumstances.

UTERINE LEIOMYOSARCOMA: malignant cousin to leiomyoma, will invade and spread inside the abdomen, often before diagnosis. Can cause notable abdominal enlargement among other symptoms. Ovariohysterectomy and chemotherapy poorly effective. Preventable with spaying except in very rare circumstances.

UTERINE FIBROSARCOMA:  very invasive malignant cancer, more common in other areas besides the uterus. Can be treated if caught early but often it will have already invaded other tissues (metastasize)   before diagnosis. Ovariohysterectomy and chemotherapy are possible but mostly ineffective if metastasis has occurred. . Preventable with spaying except in very rare circumstances.

UTERINE ENDOMETRIAL ADENOCARCINOMA: A very common uterine tumor, usually occuring in old cats. This tumor will metastasize but will remain inside of the uterine body to make complete removal possible if caught early. This tumor can metastasize to lungs, heart, abdominal organs and the brain. Preventable by spaying.

MAMMARY GLAND NEOPLASIA: the third most common type of tumor in female cats comprising as many as 20% of all tumors the queen may have. Can be almost completely prevented by spaying before the first heat as these tumors are highly hormone dependent. Cats spayed after 2.5 years of age have a risk or incident rate 7 times higher than cats spayed before the first cycle. Most tumors occur in cats 9-11 years of age and are found primarily in the breasts closer to the tail.


SERTOLI CELL TUMOR: usually small and benign but can grow very large as part of a retained testicle. Can produce estrogen, which is the most severe effect of the tumor, causing liver and bone marrow damage. Often curable if caught early or chemotherapy may be needed.  In cats with high estrogen levels surgery can be risky. Neutering is preventative.


PROSTATIC ADENOCARCINOMA: malignant tumor,  seen more often in cats that have not been neutered. This tumor causes enlargement of the prostate gland; prostate gland enlargement will often be quite irregular.  Also, this tumor can cause urinary tract blockage, weakness, pain, bleeding from the penis, and weight loss. Spreads to areas inside the pelvis and sometimes other organs. There is no treatment effective towards a cure but neutering may slow growth of the mass. This tumor is rarely seen in castrated males, neutering considered preventative.

Additional Reading

The Effects of Neutering

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