Everyone wants to live forever, and science has long sought to deliver that promise—always staying one step ahead of imagination in the search for the fountain of youth. For Serge Voronoff, the answer to this age-old mystery was simple: transplant chimpanzee testicles into humans.
Born in Russia in 1866, Voronoff studied medicine in Voronezh before emigrating to France, where he trained under the Nobel Prize-winning surgeon and eugenicist Alexis Carrel. From Carrel, he learned transplantation techniques and likely developed his unhealthy fascination with xenotransplantation—the practice of grafting organs or tissues between species. In 1895, he relocated to Egypt, where he spent the next 15 years studying the effects of castration on eunuchs—a formative experience that shaped his later research into rejuvenation.
By 1899, Voronoff had begun experimenting in earnest with glandular transplants, building upon the work of Charles-Édouard Brown-Séquard, who famously ground up dog and guinea pig testicles and injected them under his own skin. Voronoff’s early work focused on thyroid gland transplants from chimpanzees into humans suffering from thyroid deficiencies. Somehow, the results were promising enough to attract substantial financial backing—most notably from millionaire Evelyn Bostwick, heiress to the wealthy Bostwick family, whom he later married.
But Voronoff’s next phase of experimentation would be more suited to the plot of a horror film than a medical journal. Around 1917, he began harvesting testicles from executed prisoners and transplanting them into the scrotums of his wealthy clients. Demand quickly outpaced supply, and when he ran out of virile, criminal testicles, Voronoff turned to chimpanzees as his next best option.
On June 12, 1920, Voronoff completed his first chimpanzee-to-human testicle transplant. The procedure involved grafting a thin slice of chimpanzee testicle onto the human recipient’s own. According to Voronoff, the surgery was a rousing success. As news spread, wealthy men from around the world lined up for their chance to receive a “monkey gland.”
In 1921, Voronoff’s wife died, leaving him a small fortune. Now flush with resources and an endless supply of eager clients, he established clinics in Paris and Algiers. By 1926, he had performed thousands of procedures, earning worldwide notoriety and the unusual moniker “The Monkey Gland Man.”
Voronoff’s research wasn’t limited to men. He also experimented on women, transplanting chimpanzee ovaries into human subjects. Pushing ethical boundaries even further, he attempted to inseminate a chimpanzee with human sperm, hoping to create a hybrid. While in a parallel universe, this might have led to Planet of the Apes, in ours, it was mercifully a failure.
As any modern sixth-grade biology student could tell you, grafting foreign tissue onto the human body doesn’t work—at least not in the way Voronoff imagined. At best, the body would absorb the tissue as scar tissue, which at the time may have been mistaken for assimilation. More often, the immune system would reject it, leading to serious complications or even death. It was inevitable that scientific reality would catch up to Voronoff, bringing his bizarre run as a virility vendor to an end.
Any positive effects from his transplants were likely due to placebo effects or clever marketing. Meanwhile, failures and complications were kept secret—either by Voronoff himself or by patients too embarrassed to admit their monkey gland experiment had gone awry. By 1935, the procedure was obsolete, and Voronoff’s research was widely discredited by the medical community.
Yet, despite his scientific failures and dubious ethics, Voronoff was not entirely off the mark. His research helped pave the way for modern hormone therapy, and his work indirectly foreshadowed treatments like testosterone replacement therapy, Viagra, and Cialis.
Voronoff died in 1951, his death inspiring mocking headlines that declared:
“Monkey Gland Man Dead at 85.”
Jason Roberts is a Seattle-based author noted for his acclaimed western horror series The Dead Wind Trilogy as well as other works of cosmic horror infused with historical fiction. His web-based series, Dark Distractions examines paranormal mysteries, unexplained phenomena, and all things strange.
