In the tragic cases of cancer among prepubescent boys, the chemotherapy that succeeds in saving the vast majority of their lives nonetheless comes, for more than 50 percent of patients, with a shattering side effect: future infertility. Since the stem cells in their testes have not yet begun to produce sperm, these patients lack the standard option of sperm banking for future in-vitro fertilization. Geneticist Dr. Nitzan Gonen of the Mina and Everard Goodman Faculty of Life Sciences and the Institute of Nanotechnology and Advanced Materials believes there’s hope, however—in the form of a tiny artificial organ she grew in a laboratory dish.

The 2023 Krill Prize for Excellence winner for her groundbreaking research on mammalian sex determination, Gonen has successfully produced testicles organoids from neonatal mice testis. Even better: These tiny cell masses stayed alive for a full nine weeks, long enough to complete the process of sperm production and the secretion of hormones, the basic preconditions for male fertility. This achievement will allow Gonen and her team to study the process by which the bipotential gonad, or the embryonic tissue with the capacity to become either testes or ovaries, results in sex differentiation—the first step toward deciphering the cause of devastating genetic disorders of sex development. (It is also the reason for her receipt, in 2022, of a prestigious European Research Council Starting Grant.) But perhaps most important, she hopes her basic research will serve another purpose: Namely, “Therapeutic applications for male children facing cancer treatment, to allow them to father children biologically,” Gonen explains.

To that end, she is working with a gynecologist at Jerusalem’s Hadassah Medical Center who will provide her lab with frozen samples of child patients’ testicular-tissue biopsy. “If we can generate the same type of cellular growth as we did with mice testes, we may be able to bring a prepubescent boy’s testicular cells to maturity,” she says. “We then hope to grow fertile sperm in vitro, which a child cancer survivor can use in the future to have children of his own.” She also seeks to address the problem of adult male infertility, perhaps by taking patients’ somatic cells and reverting them to stem cells capable of producing sperm for in-vitro fertilization. “I’m gratified that my research can have such critical applications,” she says. “There is nothing I’d love to do more than help give the gift of life.”