Salt Lake City biotech Paterna Biosciences says it has grown functioning human sperm in a lab, then used that sperm to fertilize eggs and create test embryos. The company says the cells began as testicular tissue and were subjected to a lab-based version of spermatogenesis to produce motile sperm cells. If outside scientists can confirm that, it would mark a major shift in fertility care and instantly plunge the field into a thicket of safety and regulatory questions.
According to WIRED, Paterna claims it has worked out the molecular signals needed to turn spermatogonial stem cells into mature sperm and has shared microscope images the company says show sperm tails. WIRED also notes that none of the data has been published in a peer-reviewed journal, and no independent lab has yet verified the work.
Company claims and data
On its press site, Paterna Biosciences describes the result as "the world’s first in vitro human spermatogenesis" and posts photos it says document the lab-made sperm. The company says the resulting embryos were created only as an early validation step, not to start pregnancies, and that larger studies are planned to compare lab-grown sperm with conventional samples taken from patients.
As WIRED reported, Paterna cofounder and CEO Alexander Pastuszak, listed as an associate professor at the University of Utah School of Medicine, said, "We’ve figured out the instructions that are needed to teach these stem cells to become mature, normal sperm." According to Pastuszak, computational biology tools and a proprietary mix of growth factors were used to steer the cells through the familiar stages of spermatogenesis inside the lab dish.
Why experts urge caution
Researchers who follow the field closely say they have seen bold claims before. A French startup announced a similar achievement in 2015, a story that drew headlines and then heavy scientific scrutiny, including questions about whether full spermatogenesis had really been achieved. Coverage by MedicalXpress and others at the time underscored the broad consensus that independent replication, genetic analysis of embryos, and peer review are nonnegotiable steps before anyone talks about clinical use.
Regulatory and ethical questions
The Salt Lake Tribune reports that Paterna’s approach, which starts with testicular tissue, is expected to face years of additional research and regulatory review before it could be offered to patients. Bioethicists and reproductive medicine specialists say that as this science moves toward the clinic, it will demand strong oversight, extensive genetic screening of any embryos, and a public debate about how and when such technology should be used.
What comes next
Paterna says it plans larger lab studies that will directly compare eggs fertilized with extracted sperm to eggs fertilized with lab-made sperm, followed by close screening of the resulting embryos for physical and genetic abnormalities. The company has said clinical trials could begin as soon as next year. Reporting by Gizmodo notes that Paterna took part in the Mayo Clinic-ASU MedTech Accelerator, a credential the startup points to as part of its path toward clinical research.
For Salt Lake City and for people dealing with severe male infertility, the announcement hints at a potential new tool in the fertility toolbox. For now, though, scientists and regulators say the work will ultimately stand or fall on independent verification, open data, and years of safety testing, not on splashy claims or press materials.
