Bulldog, which was once known as a ferocious and tenacious dog breed, has become today's most popular dog breed as people have discovered that they are actually affectionate and charming. Unfortunately, the future of the favorite dog breed is now uncertain.

Because of the high demand for the medium-sized breed, bulldogs have undergone centuries of inbreeding. A new study has revealed that this breeding behavior have put their existence in jeopardy.

Published in the journal Canine Genetics and Epidemiology, the first genetic study that focused on bulldogs found out that that dog breed may be gone soon because of health reasons.

By examining the genetic diversity of 102 registered English Bulldogs used for breeding, the researchers found out that "selective breeding" that aims to change the dog's appearance has extremely altered the large regions of the bulldog's genome or genetic code.

Their low genetic diversity has made them one of the unhealthiest dog breed in the world. Among the common problems experienced by bulldogs today are difficulty in breathing, abnormal teeth, skin infections and malformed joints, Wakefield Express notes.

Infusion of new genes is needed to improve the future fitness of bulldogs. While it may seem like an easy task with new technology to guide experts, the study says that in the case of bulldogs, it won't be simple.

In an interview with National Geographic, study leader Niels Pedersen, a veterinary researcher at the University of California, said that insufficient phenotypic and genotypic diversity makes it difficult to "naturally reintroduce healthier traits into the population."

"In our estimation, it will be difficult, and possibly impossible, to back off and reverse breed the dogs," says Pedersen.

The lifespan of a purebred bulldog is below 10 years and the love for the breed should not be the cause of their extinction.

"Just because they're great apartment dogs -- affectionate, and some think they're cute and baby-like -- you can't just breed them because they're popular. That's no excuse for allowing them to be unhealthy, and that's where it is right now," Pedersen said in a separate interview with CBS News.