Scientists in China who have been genetically modifying beagles to be more muscular are being accused of animal cruelty.
Led by Dr Lai Liangxue at the Guangzhou Institutes of Biomedicine and Health, the scientists claim they're the first to successfully alter the genetic makeup of dogs.
They doubled the muscle mass of the beagles through the process of "gene editing".
"We knocked out a gene which would ordinarily stop muscles from growing, so these dogs became much more muscular," Dr Lai says.
Scientists told CBS News the idea is not to create designer pets but rather to mimic disease like Parkinson's in the dogs, and then treat them in an effort to find a cure.
Ultimately the idea is to create a safe, effective drug.
"This is just the first step, Dr Lai says. "We'll observe the muscle growth to prove the technology works."
Beagles are often used in research against the wishes of animal rights advocates.
Scientists at a lab in Shenzhen used similar technology to create "micro-pigs". In September they started selling them as pets for US$1600 each.
Then in April, another lab drew worldwide condemnation for carrying out genetic editing tests on human embryos. Some major scientific journals wouldn't even publish the work.
Dr Lai says it isn't fair that people call Chinese labs the "Wild West".
"What we do [at our lab] is for the betterment of humankind," he says. "I don't think anyone should experiment on humans before ethical questions are answered."
Dr Lai, a dog-lover, insists they need to improve accuracy. Of the more than 60 embryos they gene-edited, only two were successful.