Thousands of babies are born through in vitro fertilization every year, but for decades scientists have been unable to produce a puppy by the same method. Until now.

In July, seven beagle-mix puppies were born at Cornell University’s College of Veterinary Medicine, and the 5-month-old pups are currently being house trained.

With millions of dogs in overcrowded shelters, the world certainly doesn’t need more puppies, but scientists are hopeful that this achievement could lead to healthier pets and even save endangered canine species.

In vitro fertilization is the process of fertilizing an egg with sperm in a lab, and we’ve been doing it successfully in humans — as well as cats, cows and monkeys — since the 1970s. However, dogs presented a challenge for researchers for several reasons.

For one, dogs’ reproductive cycles are very different from humans’ because they only produce eggs, or go into heat, twice a year. Also, unlike the eggs of humans and many other species, when a dog’s egg is ovulated, it isn’t immediately ready to be fertilized. It must first mature in the fallopian tube for several days

Another issue scientists faced was a bit of bad information from a 1978 journal article. Biologists were experimenting with canine in vitro fertilization based on that data, which suggested magnesium was detrimental to sperm. However, dog sperm actually requires a bath of chemicals — including magnesium — in order to fertilize an egg.

Dog sperm has a coating of cholesterol that covers the area where DNA is stored. When the sperm enters a female dog’s uterus, these chemicals break down the coating and help the sperm propel itself, allowing it to fertilize the egg.

Armed with this new information, scientists re-created the chemicals found inside a female dog’s uterus. The result was seven puppies.

Jennifer Nagashima and Nucharin Songsasen walk puppiesNagashima and Songsasen take a few of the beagle-mix puppies on a walk. (Photo: Mike Carroll/College of Veterinary Medicine at Cornell University))

How can this discovery help man’s best friend?

Dogs are prone to cancer, and certain species of dogs are more likely to develop health conditions from eye defects to autoimmune disorders. This research could help combat such health issues.

"In-vitro fertilization itself can't help prevent disease but what it does is it gives us a way to generate embryos and then we can use new technologies — gene editing technologies — to hopefully go in and fix certain genes that cause those diseases," Alexander Travis, an associate professor of reproductive biology at Cornell, told NBC News.

Because we share more than 350 disease traits with dogs, this research may even assist in treating and curing human diseases.

Also, the ability to aid dogs reproductively through in vitro fertilization may help us save canine species threatened with extinction, such as the African painted dog and the Ethiopian wolf.

Laura Moss writes about a variety of topics with a focus on animals, science, language and culture. But she mostly writes about cats.

Beagles are first dogs born by in vitro fertilization
Scientists hope the achievement will help them create healthier dogs and bring certain canine species back from the brink of extinction.