Paterna Biosciences, a fertility biotech, has announced what it says is a world first: Growing functional human sperm entirely outside the body. The company established viability by using the lab-grown sperm to fertilize human eggs and form embryos, with early results comparable to those produced through standard IVF.
Scientists have attempted in vitro spermatogenesis – producing human sperm outside the body – for nearly a century, with success previously limited to animal models. Paterna’s approach starts from a small testicular biopsy, coaxing stem cells through the full maturation process by recreating the biological signals and conditions the body naturally creates. The resulting sperm are structurally and genetically indistinguishable from those made in the body, according to the company.
The initial focus is non-obstructive azoospermia – men who produce no sperm at all – which represents up to 20% of infertile men. Current options for this population are limited to a multi-hour surgical procedure under general anesthesia with no guarantee of finding viable sperm. Paterna replaces that with a standard office biopsy. The company also anticipates serving men with low sperm count and quality for whom IVF often fails.
“As a clinician, I often quickly reach a point with these patients where I have to look them in the eye and say there is nothing more I can do. That’s what this technology is designed to change,” said co-founder and CEO Dr. Alexander Pastuszak, a board-certified reproductive urologist and associate professor of surgery at the University of Utah. “For the first time, we can offer men who’ve been told there are no options a path forward that starts with their own biology.”
Male infertility contributes to roughly half of all cases in which couples struggle to conceive, yet there is no FDA-approved drug treatment for the condition, and the field lags an estimated 30 years behind female-focused interventions.
Paterna has raised $11.4 million to date from IVIRMA Global (part of KKR and the world’s largest IVF clinic network), Mayo Clinic, and SpringTide Ventures, and is now raising a Series A. The company hopes to enter international markets in 2029 and achieve FDA approval soon after.
