Utah Startup Says It Grew Human Sperm in a Lab. Here's What That Means.

A Salt Lake City startup called Paterna Biosciences claims it has successfully grown functional human sperm from stem cells in the laboratory and created embryos as proof the technology works. The announcement, reported by Wired, is significant—but the research has not yet been published in a peer-reviewed journal or independently verified by other scientists.

Here is what the company says happened: Researchers took stem cells from testicular tissue, grew them in a lab dish, and guided them through the same biological steps that normally happen inside the body to become mature sperm. Co-founder and CEO Dr. Alexander Pastuszak, a urologist specializing in male fertility, states that the lab-grown sperm appear to function just like naturally produced sperm when examined under a microscope and tested in the lab.

How the Technology Works

Most previous attempts to grow sperm in the lab used a roundabout approach: take skin or blood cells, rewind them back to an embryonic-like state (called induced pluripotent stem cells), then try to develop them into sperm. Paterna is taking a more direct route. It isolates spermatogonial stem cells—cells that already "know" they are supposed to become sperm—directly from a testicular biopsy. These cells then develop into mature sperm entirely in the laboratory.

The company reports that this approach has worked across dozens of tissue samples, and that a standard biopsy could eventually generate thousands of sperm. According to Paterna's account, their lab-grown sperm have gone through all the necessary cellular steps—including DNA shuffling and cell division—needed for fertilization.

The startup created embryos in the lab specifically as a test to see whether the sperm could actually work. This was a proof-of-concept exercise, not a step toward clinical use. The technology is still far from being used to create pregnancies.

Worth flagging: While the company has achieved what looks like a real milestone, the lack of independent peer-reviewed verification leaves important questions unanswered: Can other labs reproduce these results? Is the process safe? How reliable is it?

Who This Could Help

The primary candidates are men with non-obstructive azoospermia, a condition where they produce no sperm even though their stem cells are still present and functional. Currently, these men have limited treatment options. This technology could also potentially help young boys undergoing cancer treatment—sperm-forming stem cells exist from birth, so they could theoretically be preserved and developed into functional sperm later in adulthood.

Male factor infertility contributes to roughly half of fertility problems in couples, yet far fewer medical treatments exist for it compared to female infertility. No FDA-approved medications specifically treat male factor infertility, despite its prevalence. The company has also cited research showing that sperm from some infertile men carry more genetic mutations than sperm from fertile men—another reason lab-grown sperm from preserved tissue could matter.

The Commercial Path

Paterna raised $6.4 million in seed funding in October 2024 (with another $6 million in an earlier round) and projects that the eventual procedure would cost between $5,000 and $12,000—roughly in line with other assisted reproductive treatments. The company has won recognition from Mayo Clinic and Arizona State University's MedTech Accelerator.

The next steps: larger clinical studies with infertile men, followed by trials using lab-grown sperm in standard IVF procedures with embryo transfer. The company's scientific advisors include Dr. Kyle Orwig, a reproductive biologist, and Bradley Cairns, a University of Utah professor who studies sperm biology.

What Still Needs to Happen

Analysis: We have seen this pattern before—reproductive technologies originally developed to solve one narrow problem have later expanded to serve broader populations. IVF began as a solution for women with blocked fallopian tubes in the 1970s and now produces over 500,000 births annually across many different patient groups and medical situations.

Yet the jump from laboratory success to clinical use involves substantial hurdles. Growing sperm correctly requires precise control of dozens of biological processes—epigenetic changes, chromosome organization, quality checks. Even small errors can lead to chromosomal abnormalities, damaged DNA, or sperm that look normal but don't work properly. These defects may not be visible under a microscope.

Regulatory agencies have not yet established clear pathways for approving lab-grown gametes (the technical term for sex cells). Any company pursuing this path would need to run extensive safety studies, potentially track offspring health across multiple generations, and develop standardized ways to measure sperm quality. There are also ethical questions about creating embryos specifically for research.

Dr. Ryan Flannigan, a sperm retrieval surgeon at Vancouver Prostate Centre, acknowledges the work could be significant but emphasizes that rigorous independent validation is essential. Other research groups around the world are pursuing similar approaches using pluripotent stem cells—cells reprogrammed from ordinary tissue back to an embryonic-like state.

What This Means

In this author's view, if Paterna's claims hold up under scrutiny, this represents genuine progress in male fertility treatment—an area that has lagged behind female-focused technologies. The approach could eliminate the need for surgical sperm retrieval in some patients and give treatment options to men who currently have very few.

But there is still a long distance between a successful lab demonstration and a therapy that patients can actually use. The embryo creation was a proof-of-concept milestone, not evidence that the sperm are safe or effective for real pregnancies. Independent labs will need to replicate the results. Peer-reviewed studies will be essential. And regulators will need extensive safety data before approving clinical use.

The broader potential is worth noting: if this technology succeeds, it could change how we preserve fertility for young cancer patients, how we treat severe male infertility, and even how we think about reproductive autonomy and family planning. We have seen before how a breakthrough in one area of medicine can reshape entire fields. Whether that happens here depends on what comes next.