In 2003, University of Idaho and Utah State University researchers cloned three mules. The success of the cloning came about by manipulating calcium levels. Calcium affects how quickly cells divide. The researchers are hoping that calcium levels and function might explain why horses and mules develop cancer at much lower rates than humans. Because of these cloning facts and findings, they base a possible hypothesis for discovering a key to cancer on the fact that calcium imbalances are indicators of human prostate cancer and diabetes. According to a news report aired on KBCI News in Boise, Idaho, no male horse or mule has ever been diagnosed with prostate cancer and melanoma does not metastasize in their bodies.

Two of the three healthy cloned mules, Idaho Star and Idaho Gem, are preparing to race in Winnemucca, Nevada at the Mule Races and Draft Horse Challenge. The cloned mules will gain worldwide attention next week when they become the first cloned mules to participate in a sporting competition. Perhaps one day, cloned mules will help win the race in a cure for cancer.