On the heels of World AIDS Day comes a stunning medical breakthrough: Doctors believe an HIV-positive man who underwent a stem cell transplant has been cured as a result of the procedure.

Timothy Ray Brown, also known as the "Berlin Patient," received the transplant in 2007 as part of a lengthy treatment course for leukemia. His doctors recently published a report in the journal Blood affirming that the results of extensive testing "strongly suggest that cure of HIV infection has been achieved."

There’s an estimated 33 million people worldwide living with HIV/AIDS, and now doctors believe one of them may have been cured of the virus after receiving a stem cell transplant in 2007, the medical journal Blood reported.

Timothy Ray Brown, an HIV-positive American living in Germany, had leukemia and was undergoing chemotherapy, when he received a transplant of stem cells from a donor carrying a rare, inherited gene mutation that seems to make carriers virtually immune to HIV infection.

The transplant appeared to wipe out both diseases, giving hope to doctors, but Dr. Anthony Fauci, director of the National Institutes of Allergy and Infectious Diseases, who has been studying HIV/AIDS for almost 30 years, said while this is an interesting proof of concept, it’s absurdly impractical.

“It’s hard enough to get a good compatible match for a transplant like this,” Fauci told FoxNews.com, “But you also have to find compatible donor that has this genetic defect, and this defect is only found in 1 percent of the Caucasian population and zero percent of the black population. This is very rare.”