Discover the groundbreaking OHSU study transforming human egg cells from skin cells, a major advance in infertility treatment. Learn how in vitro gametogenesis (IVG) could help same-sex couples and others have genetically related children.
At A Glance: Human Egg Cells from Skin Cells
- Breakthrough: OHSU researchers created human egg cells from skin cells, fertilized to form embryos, a first in human research (Nature Communications, Sept 30, 2025).
- Lead: Shoukhrat Mitalipov, Ph.D.
- Method: In vitro gametogenesis (IVG) via somatic cell nuclear transfer (SCNT) and mitomeiosis; skin cell nucleus reprogrammed in donor egg cytoplasm, activated, and fertilized.
- Results: 77% of 82 eggs extruded polar bodies; 9% reached blastocyst stage but showed aneuploidy due to random chromosome segregation.
- Impact: Potential for same-sex couples, postmenopausal women, and infertility patients to have genetically related children.
- Challenges: Low efficiency, no recombination, chromosomal issues; 5–10 years from clinical use.
- Ethics: Concerns include “designer babies” and access disparities; study adhered to strict guidelines.
- Future: Refine mitomeiosis for precise chromosome segregation to advance IVG.
In a groundbreaking stride for reproductive medicine, scientists at Oregon Health & Science University (OHSU) have successfully transformed human skin cells into functional egg cells, or oocytes, which were then fertilized to create early-stage embryos.
Published on September 30, 2025, in Nature Communications, this pioneering study is the first to achieve such a feat in humans, offering a beacon of hope for millions grappling with infertility.
Led by embryologist Shoukhrat Mitalipov, Ph.D., director of OHSU’s Center for Embryonic Cell and Gene Therapy, this proof-of-concept work could eventually enable same-sex couples, postmenopausal women, and those with genetic disorders to have genetically related children through a process called in vitro gametogenesis (IVG).
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The Global Infertility Crisis: Why Human Egg Cells from Skin Cells Matter
Infertility impacts an estimated 48 million couples worldwide, with female factors, particularly age-related declines in egg quality and quantity after age 35, contributing significantly.
Traditional in vitro fertilization (IVF) relies on viable eggs, leaving those without them—due to medical conditions, cancer treatments, or premature ovarian failure—with limited options like egg donation or adoption.
For same-sex male couples or transgender individuals, the absence of eggs poses an even greater barrier. IVG, which reprograms non-reproductive cells like skin cells into gametes, could bridge this gap.
While mouse studies have produced live offspring from lab-made eggs, translating this to humans has been elusive until now.
Mitalipov, known for prior milestones like creating human embryonic stem cells via cloning in 2013 and facilitating a “three-parent” baby in 2016, calls the process “mitomeiosis” – a novel blend of mitosis and meiosis that reprograms skin cell nuclei to mimic egg precursors.
“This is a significant step toward developing infertility treatments for individuals without functional oocytes,” Mitalipov said in an OHSU statement.
How It Works: The Science of Creating Human Egg Cells from Skin Cells via Mitomeiosis
The breakthrough hinges on somatic cell nuclear transfer (SCNT), a technique first popularized by the cloning of Dolly the sheep in 1996.
Here’s how it works:
- Nuclear Extraction and Transfer: A donor egg from a healthy volunteer has its nucleus, containing the donor’s DNA, removed. The remaining cytoplasm, rich in cellular machinery, is retained.
- Inserting Skin Cell DNA: The nucleus from a skin cell (fibroblast), which is diploid with 46 chromosomes, is inserted into the enucleated egg.
- Inducing Mitomeiosis: The egg’s cytoplasm reprograms the skin cell nucleus, forcing it into a premature metaphase state. Unlike typical cell division, this bypasses DNA replication, inducing a reductive division that discards half the chromosomes into a pseudo-polar body, aiming for a haploid (23-chromosome) state akin to natural eggs.
- Activation and Fertilization: The reconstructed egg is activated using electroporation (a mild electric pulse) and roscovitine, a chemical that releases it from metaphase arrest. It’s then fertilized with sperm via intracytoplasmic sperm injection (ICSI).
- Embryo Development: Of 82 fertilized SCNT eggs, about 9% developed into blastocysts—early embryos suitable for genetic analysis. Sequencing revealed integration of skin-derived and sperm chromosomes, though random segregation led to aneuploidy (abnormal chromosome counts).
The study used skin cells from a family trio (parents and daughter) and an unrelated sperm donor to track chromosomes via custom amplicon sequencing (AmpliSeq).
While the process worked, efficiency was low: 77% of eggs extruded polar bodies, but only 8.8% of fertilized eggs reached the blastocyst stage, often arresting due to chromosomal imbalances.
Unlike traditional cloning, which creates identical copies, mitomeiosis aims to reduce chromosome number, mimicking meiosis.
However, unlike natural meiosis, where chromosomes pair precisely and undergo recombination for genetic diversity, mitomeiosis showed random chromosome segregation and no recombination, leading to aneuploid embryos unsuitable for implantation.
Scientific Community’s Response: Excitement and Caution
The achievement has ignited both enthusiasm and scrutiny. “This is a game-changer for fertility,” said Paula Amato, M.D., an OHSU co-author and fertility specialist.
On social media platform X, users expressed awe, with posts like: “Scientists created human egg cells from skin cells—then used them to make embryos.”
However, experts urge caution. Amander Clark, a stem cell biologist at UCLA, noted in STAT News, “It’s groundbreaking, but the low efficiency and lack of recombination mean it’s not yet viable.”
The random segregation of chromosomes, unlike the precise pairing in meiosis, results in genetic imbalances, and the absence of crossover recombination limits genetic diversity.
Experts estimate 5–10 years of refinement before clinical trials, pending rigorous ethical and regulatory approvals.
Human Egg Cells from Skin Cells: Ethical and Societal Implications
The promise of IVG is vast but fraught with ethical questions. Could it enable “designer babies” through gene editing of lab-made eggs?
Will it exacerbate inequities in access to fertility treatments? Bioethicists warn of potential commodification of reproduction, particularly for marginalized groups like LGBTQ+ families or single parents. Global regulatory disparities could also fuel “fertility tourism.”
On the flip side, IVG could preserve fertility for cancer patients or allow genetic screening to prevent inherited diseases.
Mitalipov emphasizes the research’s experimental nature: “No embryos were implanted; this is purely for scientific advancement.”
The study adhered to strict ethical guidelines, with oversight from OHSU’s Institutional Review Board and Oregon’s Stem Cell Research Oversight Committee.
Human Egg Cells from Skin Cells: Challenges and Opportunities
The OHSU team aims to refine mitomeiosis, potentially by inducing chromosome pairing and recombination to mimic natural meiosis. Collaborations with biotech firms could accelerate progress. As Mitalipov told NPR, “It’s about giving people options they never had.”
This breakthrough underscores humanity’s drive to push biological boundaries. While not yet ready for clinics, it offers a tantalizing glimpse into a future where infertility could be overcome, and the dream of genetically related children becomes reality for more people. For now, it’s a testament to science’s power to redefine what’s possible—one cell at a time.