Neutering Male Dogs: Fact vs. Fiction

Whether you are dead-set against neutering from the outset or believe it’s a mandatory procedure, informing yourself about this surgery’s pros and cons can only help your dog.

Whether your male dog needs neutering depends on a variety of factors. By: Pixabay

What are the pros and cons of neutering male dogs?

It’s a question often asked about male puppies, especially when they reach that rambunctious, playful, bonk-their-favorite-cuddly-toy phase.

Indeed, some people react emotionally about making this decision. Many (often men) are dead-set against desexing surgery, while others assume surgery is mandatory without questioning the whys and wherefores.

Take the Middle Path

Taking the middle ground is closer to the ideal path, with people making an informed decision.

It’s important to consider each male dog as an individual, then weigh up what’s best for their health and their behavior.

The arguments for neutering male dogs aren’t as compelling as those for female dogs. Hence it’s worth taking time to think through your reasons for going ahead with surgery — or not.

Don’t get me wrong; there’s definitely a place for desexing male dogs, but there are downsides, and for some males it’s the wrong thing to do. So don’t jump to conclusions right now because some of the arguments may surprise you.

Neutering isn’t a cure-all for aggressive behavior. By: homar

Fact or Fiction?

All aggressive dogs should be castrated.


Are you surprised?

For genuinely aggressive dogs, then yes, castration is advisable. It reduces levels of circulating testosterone and helps smother the flames of aggression. However, surgery should not be looked on as a cure-all.

Equally as important is working with a certified behaviorist to address the dog’s underlying issues. Indeed, using desexing as an alternative to good obedience training has limited effect.

For a subset of aggressive dogs, neutering can make their behavior worse rather than better. These are those anxious dogs who lack self-confidence. They find the world such a big, scary place that they try to keep it at paw’s length by growling, snapping and biting.

Neutering a super-anxious dog removes the boost of confidence that testosterone gives them, thus heightening their anxiety. If this sounds like your dog, then rather than rush ahead with surgery, discuss their behavior with a vet or a certified behaviorist to work out the best course of action.

Neutering stops humping.


If a mature male has an established humping habit, some of this is learned behavior rather than hormone driven. Yes, desexing may help, but there’s no guarantee. It could be a habit.

Indeed, many puppies that are the dog equivalent of toddlers (and not gone through puberty) get “excited” around toys or their litter mates. This humping is about experimentation and establishing pecking order rather than procreation, so neutering at a super-young age has limited benefit.

However, desexing males does have a role. Catch them in that sweet-spot when the behavior is sexual but before it becomes a habit, and the snip should do the trick.

Neutering prevents testicular cancer.

Fact … with a “but” attached.

The testicles are removed during surgery, so yes, neutering prevents testicular cancer.

But testicular cancer tends to be slow-growing and non-malignant (it doesn’t spread). Should an intact dog develop testicular cancer, then prompt surgery should put things right.

However, statistics show us that neutering very slightly increases the risk of prostate cancer in dogs. The bad news is that this cancer is aggressive and responds poorly to treatment.

Please note that this increased risk is only slight — so don’t panic if your dog is already neutered.

A dog’s personality may change for the better once he’s neutered. By: Myriams_Fotos

Neutering prevents diseases linked to testosterone.


High testosterone levels over a long period of time can lead to an enlarged prostate gland (a condition known as benign prostatic hyperplasia) or anal adenomas (fleshy tumors that grow near the anus).

Removing the testicles and lowering testosterone levels drastically reduces the risk of these conditions developing.

Neutering increases the risk of some other cancers developing.


Again, the increase is very slim — so slim, in fact, that vets haven’t been certain until recently. However, there is a small increased chance of developing osteosarcoma (cancer of the bone) or hemangiosarcoma (cancer of the spleen) in neutered male dogs.

This statistic is most relevant to large or giant dog breeds. The increased risk is less evident in smaller dogs to the point of not worrying about it.

When making your decision, be aware that the timing of surgery seems to play a role. A large-breed male dog that is physically mature and stopped growing when neutered seems to buck the trend for an increased risk.

Neutering will change my dog’s character.

This is a tricky one: Yes and no.

Neutering does alter character, but usually for the best. If it has a noticeable effect, it’s usually to make the dog into their “better self,” with some of the naughty kinks ironed out.

What neutering doesn’t do is change the dog from an intelligent, playful 4-legger into a characterless lump.

Neutering causes weight gain.

I’m not going to answer this one directly — it lets too many people off the hook that blame surgery for the dog’s weight gain without taking personal responsibility.

Let’s just say that a dog gains weight when they eat more calories than they burn off. Neutering doesn’t automatically mean the dog gains weight. What it does mean is their metabolism runs a tad slower — around 5% slower — no more.

Simply cut their daily portion by 5% (or switch from puppy to adult food at the time of surgery), and the dog will stay the same shape. Simple!

If you do decide neutering is right for your pet, here are some helpful tips for post-surgery care:

Neutering will change the dog’s coat.

Yes, this does sometimes happen.

For some dogs, neutering does change a smooth glossy coat into a fluffy, wavy one. It doesn’t happen to all dogs, but it does happen.

An Important Reason to Neuter

Population control!

Let’s not forget that animal shelters are overflowing with stray or unwanted dogs. Each year, over 3 million dogs find their way to rescues … of which a percentage has to be euthanized.

A male dog can detect a female in heat from miles away. One male dog that escapes and follows the call of nature could end up fathering dozens of unplanned puppies, with potentially heart-breaking consequences if those pups don’t have homes.

Also, male dogs running after a female in estrus are more likely to get hit by a car. A big cause of death in intact dogs is their hormones making them overlook road safety.

All of this makes deciding whether or not to neuter a male dog a considered decision. If in doubt, talk these issues through with your vet. Then you can decide what’s best for your dog based on their individual risks and needs.


This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Sept. 7, 2018.

Dr. Pippa Elliott, BVMS, MRCVS

View posts by Dr. Pippa Elliott, BVMS, MRCVS
Dr. Pippa Elliott, BVMS, MRCVS, is a veterinarian with nearly 30 years of experience in companion animal practice. Dr. Elliott earned her Bachelor of Veterinary Medicine and Surgery from the University of Glasgow. She was also designated a Member of the Royal College of Veterinary Surgeons. Married with 2 grown-up kids, Dr. Elliott has a naughty puggle called Poggle, 3 cats and a bearded dragon.

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