Flickr photo by powazny

As someone who is as immersed in the world of animals as I am, one topic — pet overpopulation — is something that comes up multiple times per day in conversation, especially on social media. And it's no wonder: animal rescues and humane societies are inundated with dogs and cats who need permanent homes. Although the numbers of those waiting to be adopted are not limited to young animals, the litters of puppies and kittens that are seen are certainly a stark reminder of how much work needs to be done when it comes to getting pet populations under control.

Some sad realities come to mind when I think of the problem of pet homelessness and overpopulation, like the needless suffering of many degrees and instances of euthanasia that are, in some situations, the only solution.

Educating the public about the problem is paramount: humans are the ones who have the ability to discern where the problems lie, and where the best solutions are.

First, understand that from a biological standpoint, we are in a battle with pets.

Reproductive success drives evolution, pure and simple. It's the strongest biological factor in any species. Biology has a way of taking over, jumping any hurdle that is put in its path and compensating. The pets themselves have no control over their biological drives, and therefore can't curb their behavior when it comes reproducing.

That's why spaying and neutering have been the go-to tactic to making an effort to getting pet overpopulation under control. It's safe, effective and, best of all, it's permanent.

In 1972, the American Society for the Prevention of Cruelty to Animals made a policy decision that rocked the boat: from then on, every animal adopted from their shelters had to be spayed or neutered — a real shift in forward thinking.

Now, this policy is standard when adopting from most any shelter or rescue.

But is the message of how easy and effective spay and neuter procedures are getting through to the public-at-large? That's a good question. Here we are four decades later, and we're still battling stereotypes and biology.

Some people cite the cost of the procedure as something that stands in the way of their scheduling the procedure. (It's actually pretty affordable.) Perhaps the misconceptions surrounding the idea of neutering that keep people from having it done. ('It's emasculating!')

A new frontier of pet sterilization — the non-surgical route — just might get people to rethink the issue.

Last year, I wrote about one new drug, Esterilsol, (as it's known outside of the United States), and how it was being tested for approval by the Food and Drug Administration in countries like Guatemala and the Dominican Republic.

The good news is that the drug is expected to have full approval for use by the midpoint of 2013 here in the U.S. as a non-surgical option for neutering dogs.

Known as Zeuterin in the U.S., the drug is a safer, faster and much less invasive way to sterilize male dogs age three to ten months.

It works like this: Zeuterin (a solution of zinc gluconate; zinc is a natural spermicide) is injected into each testicle — leaving it incapable of producing sperm.

No anesthesia is needed, and the procedure is much easier, compared to the traditional surgical option. For these reasons alone, zinc neutering could be a boon to shelters.

Canines who have been Zeutered have a microchip implanted or are tattooed with the letter "z".

One drawback to surgical neutering is that it involves eliminating the source of testosterone production, therefore leaving the animal no benefits of what the hormone offers — like protecting metabolic functions. With Zeuterin, testosterone is only lowered by about half.

The surgical option has been long-touted as a way to reduce mating behaviors and to calm male dogs down. Feedback given by owners and custodians of dogs who have been sterilized with Zeuterin indicate that the same behaviors have been suppressed.

For more on zinc neutering, click here to read Dr. Marty Becker's recent piece on VetStreet.

Lorrie Shaw leads the pets section for AnnArbor.com and owner of Professional Pet Sitting. Shoot her an email, contact her at 734-904-7279 or follow her adventures on Twitter.