Neutering Saves Lives by Reducing Cancer Risks

Neutering saves lives, and prevents a number of canine cancers. Here are 6 common arguments for staying intact which author Pat Miller has quickly dispelled.


Most people respond with a warm fuzzy “Awwww” reaction when they see a litter of puppies. After all, nothing could possibly be cuter than a bunch of roly-poly baby dogs tumbling and tussling together on the floor. Or could it?

Anyone who works or volunteers at an animal shelter for any length of time soon finds his “Awwww” reaction tempered by the sobering knowledge that millions of unwanted dogs and puppies are euthanized in shelters around this country every year. I know. I worked at a humane society for 20 years. While I love dogs at least as much as the next person, to this day I cannot look at a puppy without also seeing syringes filled with blue euthanasia solution, needles inserted into furry legs, and canine bodies piled up on gurneys outside the euthanasia room door.

For those who regularly deal with the hapless victims of our throwaway society, spay/neuter is a mantra. Rarely, in the shelter worker’s opinion, is there a sufficiently valid reason for not surgically rendering a dog incapable of reproducing.

The average dog owner, however, is more concerned with his own individual rights or the dog’s well-being than with the state of animal welfare in general. There is a whole host of commonly offered arguments against spaying and neutering. How valid are they?

1. Surgery isn’t natural. I would rather be responsible by keeping my dog home or on a leash than take the risks of surgery and alter my dog unnaturally.

There is some truth to this argument. Surgery certainly isn’t natural. Neither are collars and leashes, prepared dog foods, fences, veterinary care, or the daily killing of healthy “surplus” dogs and puppies. Dogs haven’t lived truly natural lives for centuries. If we are picking and choosing which parts of “natural” we want to recreate for our canine companions, we are better off not choosing this one. If we truly wanted to be natural it follows that we would then let our female dog get pregnant and have puppies every six months, and no responsible dog owner advocates that.

It’s true that every surgery carries risks, but the risks of spay/neuter surgery are minuscule compared to the dangers of overpopulation. Far more dogs die from lack of homes, from mammary tumors, prostate, testicular and ovarian cancers, and hormone-related behavior-problems, than ever die from spay/neuter surgery.

2. Sterilization will change my dog’s personality; she/he will get fat and lazy.

This concern seems valid. We have all seen spayed and neutered dogs who were, indeed, fat and lazy. But let’s think about this for a moment.

Dogs, like humans, get fat if their caloric intake is greater than the calories burned off by exercise and other physical demands. It is true that sterilized dogs often get less exercise. Male dogs who are neutered no longer escape their yards and run for miles in pursuit of females in season, or nervously pace the fence in sexual frustration trying to find a way to escape.

Spayed females dogs no longer experience the immense drain on their systems caused by growing puppies in their bodies for 63 days and feeding them for another six to eight weeks. Nor do their bodies go through the stress of reproductive-related hormonal changes that result in an expenditure of nervous energy. It’s true that sterilized dogs of both sexes are calmer and more content to stay home, but that doesn’t mean they have to be fat and lazy. It does mean they are better companions.

It’s simple: If your dog gains too much weight, cut back on food and increase exercise! I have owned a dozen sterilized dogs over the last 20 years, and not one was fat or lazy. If I noticed that one was starting to put on weight, I cut back on the kibble. Here are several tips for a simple weight-control program:

No free feeding. Your dog should get meals, not all-day snacks. In a natural environment a wild dog makes a kill (along with the rest of the pack), gorges himself, and then doesn’t eat again until the next kill. Dogs’ systems are not designed for grazing. Besides, controlled feeding increases your dog’s dependence on you, which can make your training more successful.

Measure the food. Use a measuring cup and dole out a specific amount. Eyeballing it isn’t accurate enough; we tend toward generous. “He looks a tad hungry today . . . what’s a few extra kibbles?” If we are measuring a specific amount we can instruct all family members to stick with the feeding program. A measuring cup also gives us an accurate gauge if Rover is looking a little too prosperous and we decide we need to cut back from, say, one cup, twice a day, to three-quarters of a cup, twice a day.

Weigh your dog. Pick her up and stand on the bathroom scales, then weigh yourself alone, and subtract. Weigh her once a week so you will notice sooner, rather than later, if she starts to put on pounds. If she is gaining, cut back the kibble and/or the treats.

Use the feeding instructions printed on the dog food bag as a guide, not gospel. Dog food companies seem to lean toward the generous side of meal rations. Perhaps they like you to use more of their product? I have never fed my dogs as much as it says on the bag. If I did, they would all be fat!

If you train with treats, be sure to count those treats as part of your dog’s meal ration. If he is sufficiently food-motivated you can even use his kibble as training rewards.

Give your dog plenty of exercise. Since he is no longer burning off calories in his frustrated attempts to find females (or she’s no longer making puppies), it’s your job to make sure he works out. Throw the tennis ball, a stick or the Frisbee for him for 20 minutes a day. Take her jogging or swimming. Find a doggie play-group or a local dog park (if there are none in your area, start one!) and let her work out by romping with her canine buddies. If you are a portly couch potato, your dog will likely be one too!

3. I want my (male) dog to have fun; I want my (female) dog to experience the joy of motherhood.

This is anthropomorphism at its finest. It is usually a male human who insists on leaving his dog intact, perhaps in order not to deprive his four-footed friend of the joy of sex, or maybe out of the owner’s own embarrassment at having a male dog without a full complement of male equipment. When you mention neutering, the human’s eyes may glaze over as his hands move to protect a highly valued part of his own anatomy.

Stop and think, men! If you have ever watched dogs breeding, you’ll notice that they don’t particularly appear to be having fun. They are simply driven by a powerful, undeniable, biological urge to reproduce. They rarely relax and have a cigarette afterward! Unneutered male dogs are far more likely to escape their yards, run free, risk getting shot or hit by cars, get picked up by animal control officers, and get in fights with other male dogs. If the lack of visible equipment is your concern, ask your veterinarian about “Neuticles,” artificial implants that are now available to help owners feel better about neutering their dogs.

On the other hand, if we are responsible dog owners, we don’t allow our dogs to run free and satisfy those mighty biological urges. Our choices are to neuter, and reap the benefits of having a calm, contented canine companion who stays home (and who no longer risks prostate or testicular cancer), or to keep our unneutered male strictly, safely and unhappily confined to lead a life of constant sexual frustration as he senses females in season for miles around.

The female dog, too, benefits from spaying. While many females do seem to enjoy motherhood, at least at first, by the time their babies reach the age of six weeks most momdogs are eager to escape their persistently pushy pups. There are far more life-threatening complications from gestation and birthing than there are from spay surgery. The maternal instinct can also trigger behavior problems; a significant number of dogs develop protective maternal aggression during motherhood. For some dogs this behavior goes away when the puppies are weaned and placed in new homes. Others continue to display aggressive behavior even after the puppies are long gone.

4. My dog is purebred/has papers. I can make money selling puppies. I want another one just like her. All my friends want one of her pups. I already have homes lined up for the puppies.

Certainly, if we are to continue enjoying purebred dogs, someone has to breed them. Why shouldn’t that someone be you? Maybe because there is a lot more involved in responsible breeding than just putting two registered dogs of the same breed in the same room together.

For starters, AKC papers are not an assurance of quality. Papers simply mean that both of your dog’s parents were registered. Ostensibly. Every month, the AKC Gazette publishes names of breeders who have falsified records, or at least kept records poorly enough that the organization revokes their registration privileges. Even if your papers are accurate and your dog’s parents were both champions, that doesn’t mean your dog is breeding material.

The responsibilities of breeding should not be taken lightly. If done properly, it is an expensive, time-consuming activity. Prospective canine parents must be checked for hip dysplasia, eye problems (progressive retinal atrophy), and any other genetic health problems specific to your breed. Dogs intended for breeding should be outstanding representatives of their breed. If you plan to breed, you need to be willing to campaign your dog on the show circuit and have experts in the breed (judges and other breeders) confirm that your Labrador Retriever is one of the best around. Then you will need to do the research to find the “right” male to breed her to; one who complements her strengths and doesn’t underscore her weaknesses.

Once you have gone to all the expense and trouble to be a responsible breeder, chances are your friends aren’t going to want to pay the prices that you will ask for your well-bred puppies. Labs can have huge litters – as many as 12-15 at a time. You may not have all the homes for them that you thought you did. Many of these will be pet, not show quality puppies. They will sell for less than the show quality pups, and a responsible breeder will have them spayed and neutered before they are sold to ensure that they are not used for future breeding.

Don’t forget to consider the additional vet bills; you want to be sure your female is in optimum health, and that the puppies get veterinary examinations before they are sold. A responsible breeder will also take back any of the puppies he has bred, at any time during the dogs’ lives if the owner can no longer keep them. Not only may you be left with more puppies to place than you had planned, you may also end up with more adult dogs than you intended to own. Chances are excellent that this hobby will cost you a hefty sum of money rather than make you rich.

Finally, consider that every friend or family member who takes a puppy from you could have provided a home for a puppy at an animal shelter or rescue group. Breed rescue groups exist for virtually every recognized breed, so if your friends have their hearts set on purebred dogs they can contact breed rescue groups or go on the breed request waiting lists that are now maintained by many animal shelters. Regardless of how many homes you have lined up for your pups, you are contributing to the pet overpopulation problem.

I want my kids to experience the miracle of birth. Understandable. When I was a kid I loved watching my dogs and cats have kittens and puppies. (Yes, we were an irresponsible pet-owning family.) But if you think this is reason enough to let your dog breed, knowing that “surplus” dogs and puppies are killed every day, then you have a harder heart than I. Your kids can watch videos that document the birth process. If you want to let them experience the joy (and hard work!) of raising a litter of puppies, sign up with your local shelter or rescue group as a volunteer foster home.

For many reasons, most shelters cannot feasibly raise litters of puppies in their kennels, and must often euthanize underage pups. Shelters are desperate for foster homes who can give tender-aged baby dogs a chance to grow up and return to the shelter for adoption when they are eight weeks old and able to withstand the rigors of shelter life. You can even solicit your friends to apply to adopt your foster pups once they have returned to the shelter. You get the joy of puppy-raising and the satisfaction of providing a community service without contributing to pet overpopulation. Win-win!

5. I live in a “no-kill city. We have solved the pet overpopulation problem so it’s OK to breed again.

“No-Kill” is a myth; it actually means “Someone Kills Them Somewhere Else.” In San Francisco, often touted as the first “no-kill” city, more than 4,000 animals are still euthanized every year at San Francisco Animal Care & Control, one short block away from the “no-kill” San Francisco SPCA. While the SPCA labels these 4,000-plus animals as “unadoptable” in order to justify the deaths and claim their “no-kill city” title, it is simply a matter of semantics, public relations, and allocation of resources.

In some jurisdictions, an upper respiratory infection (canine equivalent of the common cold) or a broken leg, both treatable, qualify a dog as unadoptable. Even if San Francisco’s 4,000 animals were truly not redeemable, surrounding communities in the San Francisco Bay Area continue to euthanize unwanted animals by the tens of thousands. Don’t kid yourself; we are far from solving the pet overpopulation problem.

6. My dog is old and my veterinarian says spay/neuter surgery is too risky.

OK, you win. This is truly a valid excuse. At some point in a dog’s life the benefits of spay/neuter are outweighed by the risks of surgery. There is no magic age when this happens; it depends on the individual dog. Follow your veterinarian’s recommendation if she tells you that sterilization is not indicated due to your dog’s age and/or condition.

My Bias Around Spay/Neuter 

I am very biased about spay and neuter because of my background both as an animal protection professional and a dog trainer. You don’t have to watch very many homeless puppies and kittens die to get strident about birth control for companion animals. After working with a few dozen dogs with hormone-related problem behavior, you “get” the value of spaying and neutering.

The pet overpopulation problem is so bad that even state governments are being forced to deal with it. A new state law in California actually defines puppies under the age of eight weeks as “unadoptable,” (thereby legitimizing the “no-kill” approach of population control through word games). Another new California law requires all dogs adopted from animal shelters to be spayed or neutered before they go to their new homes – even puppies. The advent of pediatric spay/neuter – the safe sterilization of puppies as young as eight weeks – allows a law like this to be passed, and gives animal protection workers a powerful new weapon in the pet overpopulation battle.

I love dogs as much as the next person. I love them enough to believe that each one has a right to a lifelong, loving home. Pitifully few dogs get that in today’s world. If we spay and neuter, encourage others to do the same, and take the time to teach our dogs to be well-behaved family members, maybe we will all see the day when their lives are valued enough that they all end up in lifelong responsible homes, rather than dead by the side of the road or on the euthanasia room floor.

Pat Miller, a dog trainer from Salinas, California, is a regular contributor to WDJ. 

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Pat Miller, CBCC-KA, CPDT-KA, grew up in a family that was blessed with lots of animal companions: dogs, cats, horses, rabbits, goats, and more, and has maintained that model ever since. She spent the first 20 years of her professional life working at the Marin Humane Society in Marin County, California, for most of that time as a humane officer and director of operations. She continually studied the art and science of dog training and behavior during that time, and in 1996, left MHS to start her own training and behavior business, Peaceable Paws. Pat has earned a number of titles from various training organizations, including Certified Behavior Consultant Canine-Knowledge Assessed (CBCC-KA) and Certified Professional Dog Trainer - Knowledge Assessed (CPDT-KA). She also founded Peaceable Paws Academies for teaching and credentialing dog training and behavior professionals, who can earn "Pat Miller Certified Trainer" certifications. She and her husband Paul and an ever-changing number of dogs, horses, and other animal companions live on their 80-acre farm in Fairplay, Maryland.


  1. Neutering a male ups his chances of hemangiosarcoma by 4 or more fold. Additionally, it affects their joints negatively. Additionally, it affects their other endocrine systems (Adrenals and thyroid) negatively.
    The fact that desexing decreases lean muscle mass and ups fat deposits and makes it more difficult for a high percentage of dogs to maintain a normal appetite and weight is not a trivial health problem in and of itself and it predisposes a dog to a plethora of other health problems.
    It may be that many of the endocrine, skin and obesity problems seen in pet dogs and cats can be attributed wholly or partly to desexing. Certainly in ferrets, there is credible data that suggests this is the case.

    Yes, there are many social and legal pros to having mainly desexed pet dogs in the USA. These issues are valid. But, it should never be the case that the science is brushed under the rug or falsely represented to promote the politics. Yes, if the testicles are removed then the incidence of testicular cancer goes to zero (to zero from some very low number) and by that logic, if the brain is removed, the chance of brain cancer is eliminated.

    A very valid argument to make for desexing after maybe age 2 or maybe 6 is that if we are not going to allow these adult animals to breed then we should minimize their natural, hormonally charged drive to do so as that is not fair to the animal. Certainly, if my pup displays behavior that he is suffering or if he is trying to escape or fight, etc, then I will have him neutered for his peace and safety and for mine. But, it is a myth that this is a great risk for most dogs and most households. If he does not display problem behavior then there is no reason for me to ruin his hormone balance and predispose him to hemangiosarcoma, a super fatal disease. Female dogs are apparently predisposed to mammary cancer if left intact and not allowed to breed and nurse. This is a valid concern.

    I was also involved in rescue and do not want more over population of dogs but since I will not give my dog the opportunity to breed, overpopulation is not a reason for me to rush to alter my perfect, male dog.

  2. You’ve made a valid point for the average pet owner that doesn’t know how to or want to take responsibility for their pets. Easier to neuter. For the rest of us, who are responsible, we can make our own choices and one of them may be to not desex our dogs. Not for the reasons you have pointed out here but because we take responsibility and choose not to.