The ideal solution? Replace a patient’s diseased cells with his own healthy cells—or ones that are an exact genetic match, which would be possible by using adult stem cells only if the patient had an identical twin. Or a clone. Or, perhaps more realistically, a supply of cloned pluripotent stem cells.

Using the process Ian Wilmut had developed to create Dolly, scientists theorized they could solve the tissue rejection problem once and for all (and eliminate the need to procure donated organs, blood and tissues) by creating just such a supply. They could do so by taking a skin cell from a sick patient and creating a cloned embryo reprogrammed with the patient’s healthy DNA. But instead of implanting the embryo into a womb to create an entire organism as Wilmut had done with Dolly, they could use Jamie Thomson’s stem cell extraction method to create an unlimited supply of pluripotent stem cells. Because these cells would be genetically identical to the patient’s, the challenge of finding donor cells would be overcome.

Thus, in 1998, the therapeutic cloning race began. But the problem with actually pulling this off was that scientists only knew how to clone a sheep. And the egg of a sheep is an entirely different microscopic beast than the egg of a human. This meant that those labs that opted to try to clone human embryos needed what would likely amount to thousands of human eggs with which to work. Considering the invasive, potentially dangerous procedure a woman must undergo to donate her eggs, those were going to be hard to come by. Indeed, as scientists sought to be the first to clone human embryos in the years that followed, the scarcity of eggs thwarted progress.

But there was another option. Someone could determine how to clone the embryos of the rhesus macaque monkey, which share 93 percent of their DNA with humans. With monkeys at the nation’s nine federally funded National Primate Research Centers, scientists could conceivably have access to more eggs, as opposed to relying on humans to donate theirs. But due to the expense (it would cost at least $10,000 a year to work with one monkey, but in each year 100 monkeys would be needed) and expertise that such research required, few scientists were interested. The only NPRC that opted to enter the race was Oregon’s, where a bright young researcher from Kazakhstan had just arrived.

Not long after Thomson’s discovery in 1998, Don Wolf had hired 37-year-old Shoukhrat Mitalipov, an unknown scientist who had just spent three years researching stem cells at Utah State University after earning his PhD in developmental genetics and stem cell biology from the Russian Academy of Medical Sciences in Moscow. Wolf had recruited the Kazakhstani scientist because he reminded Wolf of another brilliant postdoc he’d once overseen: Jamie Thomson.

Given the run of the lab, Mitalipov threw himself at the prodigious problem of combining Wilmut’s cloning technique with Thomson’s method, but using the embryos of primates instead. It wasn’t just the technical challenge that motivated him. One of Mitalipov’s friends in Russia had a son with leukemia. Later, his own mother would be diagnosed with Parkinson’s. Both diseases—theoretically—could be cured as a result of stem cell research.

“It became my obsession,” Mitalipov explains. “I knew I might not be able to save my mother, but my hope was that I’d one day help other people with this disease.”