Healthy Monkey Born From Frozen Testicular Tissue

A monkey was successfully born from sperm that developed in cryopreserved testicular tissue—a first for primates.

The healthy female rhesus macaque, Grady, was described in a study published in Science on Thursday, and represents new hope for boys facing infertility due to cancer treatment.

A team of US scientists sampled and froze testicle tissue from five prepubescent male macaques. As the hosts entered puberty five to seven months later, the tissue was grafted under their skin near the scrotum. Within eight to 12 months, the transplants started to produce sperm that was then used to fertilize 138 eggs in-vitro at Oregon National Primate Research Center.

Less than half were viable embryos, but scientists managed to implant 11 into six female hosts. One was successful: Grady.

The technique could potentially offer new pathways to fertility for prepubescent boys undergoing chemotherapy and radiation treatments for cancer. Roughly 30 percent of these boys experience low sperm levels later on in life, reported Scientific American. While doctors can freeze semen from adult men, options for younger males are extremely limited.

In previous studies, testicular tissue has been successfully grafted onto mice to produce healthy pups, Scientific American pointed out. But Grady is the first primate born out of this technique.

“That’s where a lot of studies stop. They just say, Okay, we’ve got sperm. Ta-da,” Kyle Orwig, senior researcher at Magee-Womens Research Institute of the University of Pittsburgh Medical Center and lead author of the study, told National Geographic. “But you can imagine just because you have sperm, doesn’t mean they’re able to fertilize or make a baby.”

Still, the experiment isn’t an exact analog for male humans. The macaques were castrated during the tissue sampling process, whereas human cancer patients are not. It’s also possible that human tissue could contain malignant cells, Inverse noted.

And because the technology exists doesn’t mean it will be accessible to everyone. In-vitro fertilization is currently a pricey and exclusive fertility option, with procedures costing as much as tens of thousands of dollars and varying widely based on insurance coverage.

“The reason that we did these studies in a non-human primate is that we thought that this was really the last step on the road to translating to the clinic,” Orwig told Inverse.

“Having produced a live-born and healthy baby, we feel that this is a technology that is ready to be tested in the clinic.”