I used to spay and neuter all my dogs. But as I got into some of the European dog sports, I started noticing that unneutered dogs seemed to have something … a maturity, a self-confidence that was hard to quantify. It wasn’t that my dogs performed less well, but they seemed like perpetual kids, caught in a particular developmental stage and never really maturing. At the time, I had no “scientific” way of proving this other than through my own observation with my dogs and the dogs I worked with. But it led me to question general recommendations on neutering.

Let’s dig in

Shelters and rescue organizations promote early spay/neuter as a way to reduce the number of unwanted animals. (Early is defined as around the six-month period or before, with many being fixed at 8 weeks.) This is a great goal—but it seemed to me that there had to be unintended consequences. After all, the sex hormones are also the growth hormones. If you remove or alter sex hormones in young animals, what does that do to their growth and development?

Well, it turns out that it does a lot. It can be hard to take a good look at all the data, because some of it is specifically about dogs that are fixed when they’re young (and young is defined in different ways), and some of it is on de-sexing animals in general. There’s also a lot of it. We could spend hours and hours on this one topic. I don’t want to bore you to death, so I am just going to touch on some of the few issues.

One caveat: I am not saying that you shouldn’t fix your dog, or telling you when you should do it. My only goal is to offer some information from the “other side.” Later or alternative spaying and neutering is getting some attention these days, and some vets do recommend waiting–but the general practice is to spay or neuter quite young. There’s a lot of pressure to do it.

Health problems

There are a LOT of health issues at stake here. Here are some of the most common:

• Hip dysplasia and other orthopedic issues. One study showed that dogs fixed early are twice as likely to have hip dysplasia. It also leads to 3 times more patellar luxation and increases the likelihood of cranial cruciate ligament rupture. (These are just a few examples of the many studies that have been done on orthopedic problems.)
• Endocrine imbalances and related diseases. You’ll see more hypothyroidism, adrenal disease like Cushing’s, and pancreatitis with dogs fixed when they’re young. See what this vet has to say about her firsthand experience.
• Many proponents point out that early spay/neuter reduces testicular and mammary cancer risks. It is true for testicular cancer—but testicular cancer strikes very few dogs. The research appears to be faulty for mammary cancer. What is true is that spaying/neutering increases other cancers exponentially—heart, bone, spleen, bladder, prostate, lymphoma, mast cell, and more. (There are many, many more studies corroborating this.)
• Cognitive impairment in older dogs. According to this study, it seems that circulating testosterone and estrogen in aging dogs is protective against cognitive impairment.
• Incontinence. Spaying a female dog increases incontinence. The same might be true of fixing male dogs.

Behavioral problems

It gets even worse. You’ve probably heard that spaying or neutering minimizes aggression in dogs. Not true. It also alters other behaviors, which I find fascinating in light of my first observations of the difference between altered and unaltered dogs. My intuitive feeling is that dogs get “trapped” in juvenile stages without maturing. This is just a sampling of the information that’s out there:

• More aggression. This is interesting: “…the scores of the spayed bitches showed a significant increase [of aggression] compared with their controls.” And so is this: “Relative to intact female dogs of at least 1 year of age, the odds ratio for having bitten a member of the household was highest for neutered male dogs, followed by neutered female dogs”
• Higher reactivity. “Ovariohysterectomy of 5-10 month old German Shepherd bitches specifically, and perhaps bitches of any breed generally, may induce an increase in reactivity.”
• Other behavioral disorders. “Dogs gonadectomized at ≤ 6 months of age had significantly increased odds of developing a behavioral disorder.” Ditto excessive barking, growling at family members, and noise phobias.

Some additional resources

If you got lost in the scientific studies above, here are two great documents that go into more detail, and list some of the pros and cons:

• Early Spay-Neuter Considerations for the Canine Athlete: One Veterinarian’s Opinion
• Long-Term Health Risks and Benefits Associated with Spay/Neuter in Dogs

So what should you do?

I can’t tell you what to do. I’m not a vet, and I don’t play one on TV. I can only tell you what I do.

My first preference is for leaving dogs intact. But I’m realistic; it’s not always possible. For instance, it is really hard to keep a female dog isolated from potential puppy daddies when she’s in heat. If at all possible, I prefer to wait until the female is about two years old. A lot of vets now say 18 months, but I personally don’t think that’s long enough. The same is true for male dogs, except I generally wait until they’re about three.

There are also alternatives to sterilizing dogs, such as vasectomies and ovary sparing spays. My feeling is that it’s much better to leave the hormones that nature intended them to have. If you want more details, here’s a group that can help.

Spaying/neutering is final; there’s no going back. Before you do it–particularly early– I encourage you to look at the research (this article only scratches the surface) and consult with your vet. Then you can make the right decision for you and your dog.