Spaying and neutering your dog: pros and cons

Updated November 9, 2026 · 5 min read

To fix your dog or not? There's no single right answer for every dog. It depends on sex, breed, age and how your dog lives. Here's what the surgery really does, what it can make worse, and what to ask your vet.

Neutering, spaying or sterilization?

The words get mixed up a lot. Neutering removes a male dog's testicles, and spaying removes a female's ovaries and usually the uterus. Either way, the body stops producing sex hormones. Sterilization in the strict sense, such as a vasectomy or tubal ligation, only blocks the reproductive tract. Hormones keep working and the dog behaves as before, but can't have puppies. Vets rarely perform it on dogs.

The case for spaying or neutering

• No unplanned litters. This is the main argument, especially if your dog ever mixes with other dogs unsupervised.
• No more heat cycles. A spayed female stops bleeding twice a year, and false pregnancies and weeks of extra vigilance on walks go away.
• Protection from pyometra. This uterine infection is fairly common in older unspayed females and can be fatal. After spaying it practically never happens.
• Fewer mammary tumors. The risk tends to be lower in females spayed young, though newer reviews show the evidence is weaker than once claimed.
• Male health. No testicles means no testicular cancer, and benign prostate enlargement becomes less common.
• Less roaming. Males usually wander less after females in heat, and some mark less.

The case against

• Surgery and anesthesia. The risk is small but not zero. A spay is the bigger operation, since it enters the abdomen.
• Weight gain. Fixed dogs burn fewer calories and are often hungrier. Watch portions, and see how much a dog should eat.
• Urinary incontinence in females. It affects some spayed females, more often in large breeds, and can usually be treated.
• Joints and some cancers. University of California studies link early neutering in certain large breeds, including Labradors, Golden Retrievers and German Shepherds, to more joint problems. The results vary from breed to breed.
• Coat changes. In some breeds, like the Cocker Spaniel, the coat can turn denser and harder to care for.

Behavior: what it fixes and what it doesn't

Surgery affects hormone-driven behavior such as roaming, marking and interest in females. It won't teach your dog to listen, and it won't fix fear or barking from boredom. In fearful dogs it can even deepen insecurity. Your dog won't lose their personality or stop being watchful. If behavior is your reason, ask your vet whether a hormone implant is available in your country. It lasts about 6 to 12 months and shows ahead of time how your dog acts without testosterone. For aggression or strong fear, bring in an experienced trainer too.

The best age to spay or neuter

No single age suits every dog. Small breeds are often done between 6 and 12 months. For large and giant breeds, vets usually suggest waiting until growth is finished, which can mean 12 to 24 months. Females shouldn't be spayed during heat or a false pregnancy. Vets often choose a date 2 to 4 months after a heat, and some spay before the first one. And one myth to drop: a female never needs to have a litter to be healthy and content.

At a glance: male and female

Prices depend on your dog's size, your area and the method, and low-cost clinics can be far cheaper. Build it into your budget from the start, as covered in our first-year puppy cost guide. Dogs from a shelter are often fixed by the time you adopt them.

Care after surgery

On the first day your dog will be tired and need quiet. For the next 10 to 14 days the incision must not be licked, so use a cone or a recovery suit. Stick to short leash walks with no running, jumping or swimming. Check the wound every day: redness, swelling, discharge or unusual lethargy mean it's time to call the vet. Once your dog has recovered, weigh them and adjust portions to their weight.

How to decide

Ask yourself three questions. Could your dog get to a female, or your female get to males? Can you manage heat cycles twice a year? What breed is your dog, and how old? Then talk it through with a vet who knows your dog. A good decision starts with your dog, not with what worked for the neighbors.