Artificial testicles could advance treatments for male infertility

By Stephanie Srakocic | Fact-checked by Davi Sherman
Published March 19, 2024

Key Takeaways

  • Researchers have developed lab-grown testicles from immature testicular cells. Testicles survived for nine weeks in the lab.

  • Additional testing will determine whether these lab-grown testicles are able to produce sperm.

A team of researchers recently produced and tested artificial testicles. The artificial testicles were cultured from the immature testicular cells of neonatal mice. In laboratory testing, researchers maintained these artificial testicles in culture for eight to nine weeks. This period is notable, as sperm production and hormone secretion in mice takes 34 days. The research was led by Nitzan Gonen, PhD, at Bar-Ilan University’s Goodman Faculty of Life Sciences and the Institute of Nanotechnology and Advanced Materials and published in a recent International Journal of Biological Sciences issue.[]

Early stages of meiosis were observed during testing. Additional research will be needed to determine whether these models can produce sperm cells. If they can, this could lead to the production of sperm in a laboratory. The innovation has the potential to be a breakthrough treatment for infertility.[] 

As the study’s authors note:

“If these organoids are able to fully mimic the functionality of adult testis, we would expect them to be able to produce haploid sperm in vitro. This ability could be revolutionary and enable infertile patients to have a biological child. Major advances have been developed in recent years with regards to in vitro gametogenesis, mostly on the oocyte side…We hope that this study, and next to follow, will pave the way to enable us to produce fully functional sperm in vitro.”

Dr. Gonen hopes that artificially created testicles could also produce testosterone, acting as fully functional testicles. She believes that they could possibly help treat multiple conditions that affect male sexual development and infertility, and that they‌ might help broaden our understanding of these conditions.

The study’s authors suggest that producing artificial testicles could also be a means of addressing concerns such as fertility-related side effects of cancer treatments in children, writing:[] 

“Development of cancer in pre-pubertal boys followed by chemotherapy and radiation treatments leads to 1 in 3 boys remaining infertile…Currently, no treatments are available to restore male fertility in such patients. These children are often offered testicular tissue storage, and while live births have been reported from preserved ovarian tissues, none have been reported from testicular tissues…It will be interesting to explore whether the settings developed here could apply.”

Organoids and future treatments

The artificial testicles grown by Dr. Gonen and her team are small artificial organs known as organoids. In recent years, there’s been increased interest in the development of organoids. Researchers have created organoids of multiple organs. They’ve demonstrated benefits when used for testing new treatments, as the tiny organs mimic the function of full-grown organs. These small-scale, lab-grown organs can be used to study treatment reactions, cancer progression, and more. Additional studies have suggested that organoids could be useful for regenerating tissue.[][]

Developments in fertility treatments 

Statistics show that fertility rates around the globe have declined in recent years, but the past decade has brought forward several new fertility treatments. New developments can address concerns about decreasing fertility and can help increase options for LGBTQ and older couples. For instance, INVOCELL technology allows IVF-created embryos to be incubated in the vagina before being transplanted into the uterus. This development can bring down the cost of IVF for people trying to conceive and can allow both partners in a lesbian couple to participate in physically carrying a child.[][] 

Researchers have also worked to re-create key components of fertility. Multiple scientific groups are developing ways to create sperm and egg cells using stem cells. In 2016, British researchers broke the record for growing human embryos in the lab by keeping them alive for 13 days. These longer-surviving embryos could provide insight into embryo growth and development, which could lead to new treatments. In March 2024, researchers from the Oregon Health & Science University published trial results from an infertility treatment technique that turned skin cells into an egg that was capable of producing viable embryos.[][][] 

Additional research has focused on improving existing treatments. Freezing eggs isn’t new, but it’s experienced improved outcomes in recent years. IVF is a standard infertility treatment, but newer minimal stimulation IVF is a milder option with fewer side effects. Donor eggs have become a relatively common fertility option. Recent advances have made donor embryos an increasingly popular choice for treating fertility issues.[][][]

Surgical options have long existed as fertility treatment options, but uterine transplants are now a possibility. This development is still in its infancy but has so far been shown to be safe and effective. In a 2022 study on people in the United States who underwent uterus transplants between 2016 and 2021, a 74% graft survival rate at one year was observed.[]

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