Testicular organoids may one day offer hope to childhood cancer survivors facing infertility who want to start a family
By Anja Elsenhans • November 10, 2025
Science Explained
As a male patient, what would you do if you knew you might face fertility issues in the future? For adults, the answer is often simple: sperm banking. But for young cancer patients who have not yet gone through puberty, sperm banking is off the table.
Infertility is a common side effect of cancer therapy. Saving a child's life is, of course, the top priority. But they might not be able to fully understand the impact infertility will have on their future. As childhood cancer survival rates keep improving, more and more adult survivors are facing infertility as a consequence of their treatment.
Organoids may be one piece of the puzzle to help childhood cancer survivors live life on their own terms following cancer treatment. Organoids are lab-grown “mini organs” that can mimic the structure and function of real organs. This makes them a versatile tool for research with many potential real-world applications. Scientists are currently exploring how testicular organoids could one day offer a new path toward regaining fertility.
Making sperm
In the testicles, specialized cells – called germ cells – develop into sperm through a process known as “spermatogenesis”. Young males start to make sperm at the beginning of puberty. But until then, the germ cells within the testicles are immature, waiting and preparing to become sperm one day.
With the start of puberty, the wait is over. Germ cells begin the complex and multi-step process of spermatogenesis. It takes about 2 months for a germ cell to complete all steps of this process and become sperm. If those germ cells are damaged before puberty, because of cancer treatment, for example, they cannot go through spermatogenesis.
To tackle this issue, scientists are exploring ways to make sperm outside of the human body. Lab-grown “mini testicles”, called testicular organoids, have the potential to mimic the function of real testicles and produce sperm.
Testicular organoids today
Researchers around the world have already made testicular organoids for many species, including mice, pigs, and of course humans. Generally, cells can be isolated from a small piece of testicular tissue. The isolated cells contain a mix of different cell types found in the testicles, including the germ cells. When this mix of cells is forced into close proximity, the cells are often able to form organoids on their own.
Many testicular organoid models do a good job in mimicking the cellular architecture of the testicles. Most of them contain all key cell types found in the testicles, including the all-important germ cells. Researchers in Sweden have been able to generate rudimentary testicular organoids from the preserved testicular tissues of a childhood cancer patient.
This is a magnified view of a microwell plate with one testicular organoid in each microwell. Microwells are tiny pyramid-shaped structures that force cells into close proximity and enable organoid formation. The organoids here have just formed and are now ready for subsequent experiments. (Photo by Anja Elsenhans, the Dobrinski Lab, the University of Calgary.)
In addition to mimicking the cellular architecture of a testicle, testicular organoids should also be able to perform the main functions of the testicles: produce sperm. But so far, none of these “mini testicles” can do that.
Although producing sperm is challenging, scientists have not given up, and their hard work is starting to pay off. Making sperm is a complex, multi-step process. Germ cells must go through several stages of development before they turn into sperm. Researchers can now observe some of the early stages of sperm development happening inside human testicular organoids.
Organoids beyond the lab bench
Although this is an exciting time for reproductive research, it can raise ethical questions: Is lab-grown sperm safe, and how and when can it be used? In Canada, the Assisted Human Reproduction Act defines what is allowed when it comes to reproductive technologies. But it does not yet include clear guidelines for lab-grown sperm. As science progresses, the rules will have to evolve, too.
Testicular organoids may not be ready for clinical use just yet, but progress is steady. At the University of Calgary, Dr. Ina Dobrinski has advanced research on testicular organoids for several years.
“Sperm generated from testicular organoids is practically possible and within reach. One of the major obstacles right now is to keep testicular organoids alive long enough to support full spermatogenesis,” Dr. Dobrinski said.
In the near future, childhood cancer survivors may not only survive the cancer, but also be able to look forward to building families.
About the Author:
Anja Elsenhas completed her BSc in Medical Biology in Germany before moving to Canada to join Dr. Ina Dobrinski’s lab at the University of Calgary. As an MSc student in Biochemistry and Molecular Biology, her research focuses on culturing testicular organoids.
Stay up to date on Anja’s work here.
