Lab-Grown Human Sperm: Paterna Biosciences Announces Breakthrough

Utah startup Paterna Biosciences reports isolating spermatogonial stem cells from a testicular biopsy, guiding them through meiosis in a dish, and producing mature sperm that fertilized human eggs, yielding early embryos. The process mirrors the natural two-month timeline, and the company aims for pregnancy-initiation trials next year. No peer-reviewed paper or independent replication exists.

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Spermatogenesis in vitro succeeded in mice in 2011; a French firm, Kallistem, claimed human success in 2015, but experts doubted sperm maturity and fertilization ability. Paterna’s claim is the first to show functional human sperm that can create embryos outside the body.

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Male factors cause roughly half of infertility; 10-15 % of affected men have azoospermia yet retain stem cells. Paterna proposes a $5,000-$12,000 per-procedure price, limiting access.

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Paterna says the technology offers an option for men previously told “there is nothing more medicine can do.” The firm will compare embryos from natural versus lab-grown sperm for genetic abnormalities. Lipshultz called the work “huge” if validated; Mitchell and Hayashi stressed that safety must be proven before clinical use.

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Scientists warn extensive genetic and developmental testing is needed to rule out mutations. Financial barriers and lack of insurance coverage were noted by urologist Justin Dubin. Ethical speculation includes same-sex male couples producing genetically related offspring and “unibabies,” raising questions highlighted by Hank Greely and Hayashi.

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The findings have not been peer-reviewed, published, or independently replicated, and long-term outcomes of the embryos remain unknown.

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• “As a physician, I've sat across from far too many men and their partners and told them there's nothing more medicine can do: no sperm, poor sperm quality, repeated IVF failures,” — Dr. Alexander Pastuszak, CEO, Paterna Biosciences

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• “We successfully grew functional human sperm from their starting cells, entirely outside the human body, and then we proved they work,” — Dr. Alexander Pastuszak, CEO, Paterna Biosciences

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• “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. Apparently, they’ve identified these substances.” — Larry Lipshultz, Professor of Urology, Baylor College of Medicine

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• “We need to be confident that it’s safe before we could ever use those cells to make a baby,” — Rod Mitchell, Male Fertility Expert, University of Edinburgh

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• “We really need to prove that this kind of technology is safe,” — Katsuhiko Hayashi, Developmental Geneticist, University of Osaka

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Paterna intends to finish comparative embryo safety studies within months and, pending regulatory approval, begin pregnancy-initiation trials next year. Ongoing scientific review and ethical oversight will shape clinical adoption.

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