Scientists in China say they have used a stem cell technique to create functioning sperm for mice in laboratory dishes. 

They say the process, if proven successful in humans, could be a major step toward helping men with the most serious infertility problems.

Their findings were published today in the journal Cell Stem Cell.


Dr. Natan Bar-Chama, a male infertility specialist and urologist at the Reproductive Medicine Associates of New York, said the research is an “exciting development with tremendous potential.”

However, he told Healthline the technique needs more research, a process that could take five to 10 years.

“Nonetheless, I do feel optimistic that over the years a form of this technique will be available to a human model,” said Bar-Chama, who is also director of Male Reproductive Medicine and Surgery at Mount Sinai Hospital in New York.

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How the Process Works

In their study, the Chinese scientists coaxed embryonic stem cells in mice to turn into functioning sperm-like cells.

Those cells were then injected into egg cells and produced fertile mice offspring.

The scientists accomplished this by exposing the stem cells to a chemical cocktail that turned them into primordial germ cells.

Those cells were then exposed to testicular cells as well as sex hormones such as testosterone.

The cells then “underwent complete meiosis, resulting in sperm-like cells with correct nuclear DNA and chromosomal content,” the study authors wrote.

“We established a robust, stepwise approach that recapitulates the formation of functional sperm-like cells in a dish,” co-senior study author Jiahao Sha of Nanjing Medical University said in a statement. “Our method fully complies with the gold standards recently proposed by a consensus panel of reproductive biologists, so we think that it holds tremendous promise for treating male infertility."

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Limited but Important Use

Bar-Chama said men are the cause of about 15 to 20 percent of cases where couples are facing infertility issues.

Of those, only a small percentage involves men who can’t produce fertile sperm.

Bar-Chama said the type of treatment involved in the Chinese experiment would be used to treat those most severe cases.

Surgery, medication and the ART technique of intracytoplasmic injections (ICSI) are now available for infertile men who have obstructions, low sperm counts, or other causes of infertility.

Bar-Chama said the stem cell technique still needs to be tested in primates and then humans for effectiveness. He added the process must also be proven safe to make sure it doesn’t cause cancer or have other harmful side effects.

“The end point is not just to reproduce,” he said.

If the technology does come to fruition, it could be a medical miracle for couples who now have only adoption or donor sperm as options.

“It could provide a tremendous, emotional uplifting answer to their problem,” Bar-Chama said.

However, he cautioned the technique is still years away from being available.

“It’s not yet ready for prime time,” he said.