The Legal Issues of Dog Sterilization

hahd_animal-lawIn this section, we will discuss the legal impediments which must be overcome to achieve our goal of including vasectomies and tubal ligations as legally viable options for sterilization of our canine companions. (Although we have outlined in our Complications of Spay Surgery page our reasons that we do not favor OSS, it is logical that this procedure should also be included as a potential alternative to traditional spay). The reader must determine if their state allows the substitution of tubal ligation/OSS/vasectomy for traditional spay/neuter. If your particular state law needs to change (as does ours in California), we will explore the obstacles you may encounter, and provide the reader a strategy for success. We identify those organizations who may oppose our desired change and familiarize you with their perspective.

In the San Francisco Bay Area (California) where we live, most pets are adopted as “rescues”. In fact, the personal desire (as well as peer pressure) to “rescue” a dog versus buying a purebred dog from a breeder is enormous. Even if one were to opt to purchase a dog from a breeder, most breeders require the purchasers of dogs to sign a contract agreeing to spay or neuter their new puppy. It seems plausible that a breeder would be satisfied by a new pet owner opting for tubal ligation or vasectomy. However, with respect to adopting a dog in California (and some other states/communities), the law demands the dog be spayed or neutered.

Today 31 states and the District of Columbia require that pets adopted from shelters be spayed or neutered before they leave the facility. We believe the “spay and neuter” specific laws should be changed to “sterilization” to allow healthier hormone-sparing procedures as described on this website. Further, it does not seem that good law would take the medical decisions out of the hands of the doctors, in essence allowing legislators to mandate specific medical care. It seems proper for legislation to mandate a specified outcome (i.e. sterilization), and leave the decision as to how to best arrive at that outcome up to the doctors. Lastly, because technology may provide us superior options in the future, why wouldn’t it be advantageous to have a law broad enough to adapt to positive change?

We recommend that you verify whether the law in your state mandates spay or neuter. In those communities/states that do not allow for hormone-sparing sterilization (i.e. tubal ligation, OSS or vasectomy) for all adoptive dogs, we need to change, clarify or expand the law.

Despite the studies that support the need for change, the veterinary community is not pressing for this change, and in many cases, will be opposing it. For example:

  • Veterinary schools do not instruct their students upon the merits of, or the surgical protocol for, tubal ligation or vasectomy, despite the fact that persuasive evidence to move to an endocrine protective procedure (such as tubal ligation or vasectomy) is coming out of research at these same veterinary schools. For example, since 2013 UC Davis has produced three studies showing the increased incidence of four cancers and three orthopedic conditions in spayed or neutered dogs of three different breeds. In spite of their own findings, to our knowledge UC Davis still teaches traditional spay/neuter only.60,61,108

“The AVMA supports the concept of pediatric spay/neuter in dogs and cats in an effort to reduce the number of unwanted animals of these species. Just as for other veterinary medical and surgical procedures, veterinarians should use their best professional judgment based on the current scientific literature in deciding at what age spay/neuter should be performed on individual animals. The decision should be made by the animal’s owner in consultation with a veterinarian after discussing associated risks and benefits.”

* Please note: We first published this information on October 16, 2016. At that time, there was no mention of sterilization procedures other than spay/neuter on the AVMA website. As of July 17, 2017, the aforementioned/linked AVMA web page which advocates for spay/neuter only is no longer available via the AVMA knowledge base (i.e., Search Center) and has been effectively removed from the primary AVMA site. At that time, it was replaced by a new page entitled  Spaying and Neutering, which discusses other sterilization techniques (e.g., vasectomy, OSS).  Now in 2023, we are pleased to see this organization, which in theory represents the professional veterinary community, actually publishing a long overdue study comparing the risks and benefits of accepted methods to prevent pet overpopulation. Further, the AVMA is acknowledging the emerging evidence that it may be preferable to perform alternative sterilization procedures which preserve hormonal balance. What is disappointing, is the suggestion that delaying spay or neuter may eliminate the risks these procedures create for health and behavior in dogs. This qualification is not only incorrect, but dangerous as the members of the veterinary community who favor spay/neuter will ultimately press dog guardians to spay or neuter at an older age. Spay and neuter are NEVER the best option for sterilization of a healthy dog at any age. Exceptions might be made for dogs with specific health considerations.

  • The ASPCA website in 2016 endorsed pediatric spay/neuter as the only procedure to achieve pet sterilization. The ASPCA website specified the source of information regarding spay/neuter that they have chosen to rely upon, i.e., Dr. Margaret Root Kustritz (who we will discuss below). At that time, according to the ASPCA website:

Much of the information here on the long-term safety of pediatric neutering is a summation of the findings in a 2007 article on determining the optimal age for gonadectomy by Dr. Margaret Root Kustritz, a veterinary theriogenologist (reproductive expert) at the University of Minnesota College of Veterinary Medicine.182*

* It appears our pleas for the health and well-being of every dog have not fallen upon deaf ears at the ASPCA. Today, the ASPCA website states the following:

“To decrease the number of animals entering shelters, the ASPCA supports the pre-adoption sterilization of all shelter animals, including early-age sterilization.”

It is still informative to examine how and why Dr. Kustritz’ review of the scientific evidence is so inconsistent with the Rutgers University systematic review we utilized as the basis for much of this website. Both documents were produced in the same year and referred to many of the same studies, yet came to diametrically opposed conclusions. We believe the title and statement of intent for each of these reviews reveals reasons for the discrepancy.

The systematic review we relied upon throughout this site was entitled, “Long-Term Health Risks and Benefits Associated with Spay / Neuter in Dogs”. The foreword, written by Dr. Katz, Associate Professor and Chair of Animal Sciences at Rutgers University states:

At some point, most of us with an interest in dogs will have to consider whether or not to spay / neuter our pet. Tradition holds that the benefits of doing so at an early age outweigh the risks. Often, tradition holds sway in the decision-making process even after countervailing evidence has accumulated…One cannot ignore the findings of increased risk from osteosarcoma, hemangiosarcoma, hypothyroidism, and other less frequently occurring diseases associated with neutering male dogs. It would be irresponsible of the veterinary profession and the pet owning community to fail to weigh the relative costs and benefits of neutering on the animal’s health and well-being. The decision for females may be more complex, further emphasizing the need for individualized veterinary medical decisions, not standard operating procedures for all patients. No sweeping generalizations are implied in this review. Rather, the author asks us to consider all the health and disease information available as individual animals are evaluated. Then, the best decisions should be made accounting for gender, age, breed, and even the specific conditions under which the long-term care, housing and training of the animal will occur. This important review will help veterinary medical care providers as well as pet owners make informed decisions…”

We chose to rely upon this systematic review because the purpose of this review was solely to inform, and we did not detect an inherent bias in the selection or interpretation of studies included in this review.

“Clinicians should determine to what extent the findings of a systematic review are valid on the basis of whether the investigators assessed and considered risk of bias during the interpretation of findings.” –The Journal of American Dental Association; September 2016 Volume 147, Issue 9, Pages 720–728

Additionally, this review respected two extremely important tenets of competent medical care. First, do no harmThis review emphasizes the need to provide all patients (family dogs and shelter dogs alike) competent care which considers individual patient needs, is effective and does not harm the patient. Second, there is acknowledgment of the need for “informed consent“-providing a dog guardian all the known risks and benefits of a proposed procedure, and allowing the guardian to be an active participant in determining the care to be provided. When there is no guardian, Dr. Katz expects the veterinary medical care provider to make good decisions for the shelter dog, in anticipation of the long-term goal of finding the shelter dog a forever home.

On the other hand, the review authored by Dr. Margaret Root Kustritz which the ASPCA relies upon is entitled: “Determining the Optimal Age for Gonadectomy of Dogs and Cats”.


“For those who believe, no proof is necessary. For those who don’t believe, no proof is possible.” – S. Chase

Although this review claims, “the objective for the information reported here was to provide a review of the scientific evidence which could be used by veterinarians to counsel clients appropriately on this issue“, the title, and the specific reference to only the gonadectomy procedure (i.e., spay/neuter),  indicates the conclusion to spay or neuter every pet has been pre-determined. The controversy in Dr. Kustritz’s mind is only as to the timing of the spay or neuter. When evaluating the same aforementioned studies which found increased risk of osteosarcoma, hemangiosarcoma and hypothyroidism in neutered males, Dr. Katz of Rutgers indicates that it would be “irresponsible” to ignore these findings, while Dr. Kustritz chooses to conveniently disregard the findings of each and every one of the studies with the dismissive retort, “an exact cause-and-effect relationship has not been defined.”

Dr. Kustritz’ review concludes in part:

Animals housed at humane societies should be treated as a population. Societal benefit resulting from gonadectomy of unowned dogs and cats in the United States outweighs all other concerns. Male and female dogs and cats should be spayed or castrated before being offered for adoption by humane organizations.”

We recognize spay/neuter is a means to an admirable goal. However, is it ethical to compromise the right to a healthy and happy life for the individual dog for the perceived “greater good” of controlling dog overpopulation?  A 2012 Texas A&M research paper 99  titled, “Inconvenient Desires: Should We Routinely Neuter Companion Animals?”, explores this very question. Summarizing their conclusions:

Routine neutering of companion animals raises significant ethical questions and from some ethical perspectives, looks highly problematic. In the case of male dogs and the long-term health risks involved, routine neutering is not morally justified.

The Rutgers review and many of the recent studies reviewed indicate it is imperative to consider the specific characteristics of each dog before deciding upon spay/neuter or any care plan. Alternatively, in 2016 when this website was first created, Dr. Kustritz, the AVMA, and the ASPCA believed dogs must be spayed or neutered; the issue in question was at what point in the dog’s development the spay or neuter should take place. It was also their contention that if a dog is in a shelter, the health and well-being of the shelter dog is subordinate to the mantra that they must not reproduce. We see this as a thinly veiled admission that traditional spay/neuter damages the health of many dogs, yet the veterinary community has decided to continue the practice.

Likewise, this new study published in the AVMA Journal in 2023 acknowledges that OSS and vasectomy are safer, healthier procedures to prevent pet overpopulation and can confer a longer lifespan, yet still opines that “Delaying traditional spay-neuter surgery could offer similar benefits”.  The last statement is clearly inconsistent with the findings of the current study. The idea of delaying spay or neuter until a dog has reached physical maturity as suggested in this study may help prevent orthopedic deformities, but the lifelong hormonal disruption and the resultant metabolic and behavioral issues remain. Spay or neuter is not appropriate for a healthy dog at any age. The proof is offered on the pages of this website.

The veterinary community refuses to unconditionally acknowledge that spay/neuter has been harmful to the health and behavior of millions of dogs. Take a few minutes to view Dr. Becker’s 2016 interview on this website. She offers an apology to all dog guardians and dogs that she injured by spaying or neutering these dogs. She acknowledges at the time she believed it was the correct procedure to prevent pet overpopulation. The science has changed her mind.  Shelter dogs may not have a guardian at the time sterilization is contemplated/completed, but the intent is to adopt them out to a loving home. Is there no concern for the dog’s long term well being?  What of the humans who will be forced to watch this new member of their family struggle with cancer, behavioral, orthopedic and metabolic maladies, agonize over whether they can afford to pay for the treatments that can be administered, and suffer along with their best friend with respect to the damage that cannot be resolved? Over time, we have struggled with these questions, and we believe the information provided on our “Hidden Cost of Spay/Neuter” and “Corporate Influence” pages provide the best explanation of this sorry situation.

It is time to revisit this topic with lawmakers and provide them with the new, updated scientific information and request the law specifically allow for alternative methods of sterilization including tubal ligation, OSS or vasectomy as well as any other procedure that may become available that is not disruptive to the hormones and the long-term health of the dog. We have just pointed out the specific viewpoints of the veterinary schools, national veterinary organizations, and animal welfare organizations to alert you to the fact that any and all of these entities may well be opposing your proposed change in the law. What follows is a checklist of points that need to be made to persuade lawmakers:

  • Most spay/neuter laws were written with the belief that spay/neuter was not only essential to prevent pet overpopulation, but also healthier for the dogs. Lawmakers were provided this information by the veterinary community. It is clear the lawmakers had no intent to injure or harm any dogs. For example, the California law contains a provision,

If a veterinarian licensed to practice veterinary medicine in this state certifies that a dog is too sick or injured to be spayed or neutered, or that it would otherwise be detrimental to the health of the dog to be spayed or neutered, the adopter or purchaser shall pay the public animal control agency or shelter, society for the prevention of cruelty to animals shelter, humane society shelter, or rescue group a deposit…

The information on this website should be persuasive as to the ill effects of spay/neuter. Further, if the veterinary community claims there is not enough data to change the current spay/neuter recommendations, we suggest the lawmakers be reminded of the massive amount of data that establishes serious medical outcomes for humans and wildlife exposed to environmental “endocrine disruptors“. This should be persuasive as a means to settle the controversy as to whether the endocrine disruption of spay/neuter is beneficial or harmful.

  • The Parsemus Foundation has created a directory of veterinarians in practice who are willing to perform some or all of the current hormone-sparing sterilizations–tubal ligations, OSS and vasectomies. They could be effective advocates you can ask to communicate with lawmakers. One veterinarian we have been fortunate to communicate with is Dr. Karen Becker (Mercola Healthy Pets). She courageously advocates for hormone-sparing sterilization because she personally recognized that dogs she spayed and neutered as a new veterinary practitioner were returning some five years later with serious medical problems due to their spay or neuter.

“Public health ethics is the application of relevant principles and values to public health decision making. In applying an ethics framework, public health ethics inquiry carries out three core functions, namely:

1. identifying and clarifying the ethical dilemma posed,

2. analyzing it in terms of alternative courses of action and their consequences, and

3. resolving the dilemma by deciding which course of action best incorporates and balances the guiding principles and values.”

With respect to item #1 above, the ethical dilemma is the need to curb pet overpopulation while striving to maintain the health and well being of our dog population.

With respect to item #2 above, the current course of action (mandatory spay/neuter) is one alternative. However, over time, ongoing studies have shown spay/neuter to have serious negative health consequences that were not known at the time this public policy was instituted. Further,  experts such as Dr. Jed Rogers, senior vice president of Animal Health Services for the ASPCA, acknowledge there is a lack of scientific evidence proving that neutering has helped reduce the number of unwanted cats and dogs. Permanently damaging the health and well-being of our canine companions, with no proof that there is a positive population outcome by doing so, is poor public policy indeed.

Regarding item #2, another course of action would be hormone-sparing sterilization (tubal ligation, OSS and vasectomy). This approach can effectively prevent reproduction without the negative health consequences of spay/neuter.

With respect to item #3 above, we propose to resolve the dilemma by legalizing alternative methods of sterilization which protect the endocrine function of dogs – including tubal ligation, OSS and vasectomy. This course of action best incorporates and balances the guiding principles and values.