More than one in eight American men between the ages of 25 and 49 experience some form of infertility today, according to the current data out of the U.S. Department of Health and Human Services. The problem, truly global in scope, has prompted millions in public and private research—and some of it appears to be paying off.
A Utah-based biotech firm, aided by the Mayo Clinic, announced this week that it has successfully grown mature sperm, ready to swim, out of spermatogonial stem cells in the lab. According to the company, Paterna Biosciences, the technique could soon assist men struggling with infertility to conceive biological children. Paterna, in fact, also reported that it has already successfully tested its lab-grown sperm in the generation of (at least, provisionally) healthy-looking human embryos.
“This is huge,” according to Baylor College urologist Larry Lipshultz, a specialist in male reproductive health who commented on the new research as an outside expert for Wired.
“People didn’t understand, or had never figured out, what growth factors you have to supply to these cells to get them to become mature sperm,” Lipshultz explained. “Apparently, they’ve identified these substances.”
Molecular signals
Paterna’s cofounder Alexander Pastuszak, an associate professor at the University of Utah School of Medicine and a urologist himself, has described the firm’s work as the first major innovation in this field since the dawn of intracytoplasmic sperm injection over 30 years ago.
“We started investigating the possibility of potentially deriving sperm in vitro, and we figured out the molecular programming for spermatogenesis,” Pastuszak explained in a promotional video this past summer, “and then [we] used those learnings to develop an in vitro platform that allows us to now grow sperm.”
Paterna had first explored whether the cellular make-up of human testicular tubules, in which sperm cells mature from stem cells organically, could be cultured in the lab to aid in this process. Computational biology methods, however, eventually proved to be the more viable method. The company’s team learned to reproduce key molecular signals via ligands, a proprietary cell culture growth medium, and other processes to guide these sperm-making stem cells on their journey to become what Paterna described as “mature, normal sperm.”
Pastuszak and his team at Paterna next used these lab-grown sperm to create test embryos, intended solely as a preliminary validation of the new method’s safety (to be clear, they weren’t used to create a pregnancy). The company’s next step will be larger and more detailed research into how these methods might mesh with stem cells taken from men with infertility and further testing on still more experimental embryos for any evidence of developmental or genetic abnormalities.
Mixed signals
Paterna Biosciences’ possible breakthrough, perhaps crucially, has not yet vetted its findings via the publication of this new research in a peer-reviewed journal or an outside review.
That caveat matters because at least one other biotech company—Kallistem, based in France—has already prematurely claimed success developing sperm in the lab, only to have those results challenged by outside experts in 2015. Another prior claim to this same milestone was retracted from a journal in 2009 over allegations of plagiarism and suspicions of worse misconduct.
Nevertheless, Paterna Biosciences enjoys a pedigree that should bolster some confidence: The firm was among ten life science companies accepted last year into the MedTech Accelerator program jointly run by the Mayo Clinic and Arizona State University, which awarded the company its Disruption Award for its research.
Even if Paterna’s breakthrough holds, however, at least one reproductive health professional who spoke to Wired noted that the procedure’s cost may still prove to be a hurdle for men hoping to conceive. The company said it expects the procedure will cost between $5,000 and $12,000, a lot of cash but cheaper than the $15,000 to $30,000 typically charged for a single cycle of traditional in vitro fertilization (IVF).
Ultimately, the true cost of Paterna’s novel procedure may wind up governed by either government healthcare policies or the whims of private equity groups who have transformed fertility clinics into a billion-dollar cash cow.
“Policies that affect the affordability of IVF have major impacts on the use of IVF treatments, especially at the lower end of the income spectrum,” as Stanford health policy researcher Maria Polyakova put it in 2024. “This, in turn, means that insurance coverage of IVF ultimately affects the distribution of children across the income spectrum.”
