How Scientists Grew Egg Cells From Human Skin

In a groundbreaking scientific achievement that could fundamentally reshape reproductive medicine, researchers at Oregon Health & Science University have successfully created functional human egg cells from ordinary skin cells. This unprecedented breakthrough, announced in September 2025, represents a monumental leap toward potentially treating infertility that affects millions worldwide.

The research team accomplished what was once considered impossible by developing a novel technique called “mitomeiosis” that reprograms skin cell nuclei to become viable eggs capable of fertilization. When fertilized with sperm, these laboratory-generated eggs developed into early-stage embryos, marking the first time this has been achieved with human cells using this particular methodology.

This innovation has attracted global attention not only for its potential to revolutionize fertility treatments but also for the profound ethical questions it raises. The technology could someday offer hope to women unable to produce viable eggs due to age, medical treatments like chemotherapy, or genetic conditions. Furthermore, it opens the possibility for same-sex couples to have children genetically related to both partners, while simultaneously raising important concerns about “designer babies” and the need for robust regulatory frameworks.

Background of the Study

The landmark study was conducted by a team of researchers at Oregon Health & Science University (OHSU) in Portland and published in the prestigious journal Nature Communications on September 30, 2025. The research was led by senior author Shoukhrat Mitalipov, Ph.D., director of the OHSU Center for Embryonic Cell and Gene Therapy, along with co-author Dr. Paula Amato and first author Nuria Marti Gutierrez, Ph.D.

The research builds upon earlier work that included the famous cloning of Dolly the sheep in 1997, which used somatic cell nuclear transfer (SCNT). However, unlike traditional cloning that creates a genetic copy of one parent, the OHSU team’s approach resulted in embryos with chromosomes contributed from both parents, representing a significant advancement over previous technologies.

The primary objective of the research was to develop a proof of concept for treating infertility through in vitro gametogenesis (IVG) – the process of creating gametes (eggs and sperm) outside the human body. This particular study focused specifically on generating functional human oocytes (egg cells) capable of being fertilized and developing into embryos.

The research adhered to strict ethical guidelines and received oversight from OHSU’s Institutional Review Board as well as a Data Safety Monitoring Committee that reviewed all gamete and tissue donations. The project was supported by funding from Open Philanthropy, the Haploid Gamete Research Foundation, and OHSU institutional funds, among other sources.

How Scientists Grew Egg Cells From Human Skin

The Revolutionary Mitomeiosis Process

The OHSU team employed a sophisticated approach that differs significantly from the more widely publicized method involving induced pluripotent stem cells (iPSCs). Instead of reprogramming skin cells into stem cells and then coaxing them to become egg cells—a process that can take months or even years—researchers used a technique based on somatic cell nuclear transfer (SCNT).

This innovative process, dubbed “mitomeiosis” by the research team, represents what senior author Shoukhrat Mitalipov characterizes as a “third method” of cell division beyond the two known natural processes: “Nature gave us two methods of cell division, and we just developed a third”.

Breakdown of the Technique

• Nuclear Extraction: Researchers began by extracting the nucleus—which contains most of the cell’s genetic information—from a mature human skin cell. This nucleus contained the typical 46 chromosomes found in somatic (body) cells.
• Nuclear Transfer: This skin cell nucleus was then carefully transplanted into a healthy donor egg that had been enucleated (had its own nucleus removed). The donor egg provided essential cytoplasmic factors and mitochondria necessary for subsequent development.
• Chromosome Reduction: The key challenge was reducing the chromosome number from 46 (diploid) to 23 (haploid), which is characteristic of mature egg cells. Through the application of specific chemical signals including a compound called roscovitine, along with electrical stimulation, the researchers prompted the reconstituted egg to discard half of its chromosomes.
• Fertilization: The resulting egg, now containing 23 chromosomes with genetic material from the original skin cell donor, was fertilized with sperm through standard in vitro fertilization (IVF) techniques, specifically intracytoplasmic sperm injection (ICSI).
• Embryo Development: The fertilized egg then developed into an early-stage embryo containing genetic material from both the skin cell donor and the sperm donor.

Technical Challenges and Outcomes

The process resulted in the creation of 82 functional oocytes that underwent fertilization. However, the technique currently faces significant efficiency challenges. Only about 9% of the fertilized eggs developed to the blastocyst stage—typically reached five to six days after fertilization—which is when embryos are usually transferred to the uterus during IVF treatments.

Importantly, all resulting embryos displayed chromosomal abnormalities, either containing too many or too few chromosomes, or incorrect chromosome pairings that would prevent healthy development. This highlights the need for substantial refinement of the technique before it could be considered for clinical applications.

Potential Applications

Revolutionizing Infertility Treatment

This breakthrough holds transformative potential for addressing various forms of infertility. The technology could particularly benefit women of advanced maternal age who experience age-related decline in egg quality and quantity, as well as those who are unable to produce viable eggs due to previous cancer treatments, genetic conditions, or other medical issues.

“As women get older, their eggs get older, and aneuploidy [chromosomal abnormalities] is pretty common in human eggs, especially with aging,” noted Mitalipov. This technology could potentially provide an alternative source of eggs for such individuals.

Expanding Options for Same-Sex Couples

The research has significant implications for same-sex couples, particularly male couples who wish to have children genetically related to both partners. Since the skin cells used to create the eggs can come from any individual regardless of sex, it would theoretically be possible to create eggs from a male’s skin cells, which could then be fertilized with sperm from his male partner.

“This would allow same-sex couples (two men for example) to have a child genetically related to both partners,” said Dr. Paula Amato. This application represents one of the most socially significant aspects of the technology.

Advancing Genetic Disease Research and Prevention

The technology could also contribute to preventing genetic disorders by allowing for better screening of embryos before implantation. Additionally, it opens new avenues for studying human development and genetic diseases.

Researchers could potentially create eggs from patients with specific genetic conditions to study how these diseases manifest during early development, potentially leading to new treatments or preventive strategies.

Addressing Population Decline

Some experts suggest that technologies like this could eventually help address population decline dynamics in developed countries by significantly expanding the window for family planning. Matt Krisiloff, CEO of Conception Biosciences (a biotech company working on similar technology), noted that “outside of social policy, in the long term this technology might be the best tool we have to reverse population decline”.

Ethical and Legal Concerns

“Designer Babies” and Enhancement Fears

The breakthrough has raised significant ethical questions within the scientific and bioethics communities. One primary concern is the potential for creating so-called “designer babies,” where parents might select embryos based on desirable traits such as appearance, intelligence, or athletic ability.

“We could see more efforts to try to use it for so-called enhancement purposes — to try to get embryos that would be stronger or more athletic or more musical or better at math or more intelligent,” said Hank Greely, a Stanford University bioethicist who wrote The End of Sex and the Future of Human Reproduction. “Some people view that as a terrible prospect. Some people view that as a wonderful prospect”.

Consent and Reproductive Rights

Another significant concern involves issues of consent. The relative ease of obtaining skin cells—which can be shed unnoticed—raises the disturbing possibility of individuals using another person’s cells without their knowledge or permission to create eggs.

“We could have Taylor Swift babies all over the world. It’s a theoretical possibility, but not crazy,” said Ronald Green, a Dartmouth College bioethicist. “It’s a technology that’s very promising. But it raises a number of daunting ethical questions”.

Unconventional Family Structures

The technology could potentially enable reproductive scenarios that challenge traditional understandings of family and genetics. These include:

• “Unibabies”: Children created using eggs and sperm derived from the same individual, resulting in offspring with just one genetic parent.
• Multiplex parenting: Children with genetic contributions from more than two people.

While these possibilities remain theoretical, they raise profound questions about identity, relationships, and social structures.

Regulatory Frameworks and Governance

Currently, a regulatory gap exists regarding lab-grown gametes and embryos created through IVG. The Nuffield Council on Bioethics has highlighted the need for updated regulations to explicitly govern research and potential clinical applications of these technologies.

In the UK, for instance, lab-grown gametes would be illegal to use in fertility treatment under current laws, and the Human Fertilisation and Embryology Authority is already considering how to ensure the safety of such approaches. Similarly, in Japan, a government bioethics panel has recommended allowing creation of human embryos using lab-generated sperm and eggs strictly for research purposes, not reproduction.

Challenges and Limitations

Technical Hurdles and Efficiency

The current technology faces substantial technical challenges that must be overcome before clinical applications can be considered. The modest success rate—with only 9% of fertilized eggs reaching the blastocyst stage—indicates significant room for improvement in efficiency.

The process of chromosome reduction appears to be particularly problematic, with chromosomes segregating randomly rather than in the controlled manner seen in natural meiosis. This randomness leads to chromosomal abnormalities that prevent normal development.

Safety Concerns

Safety considerations represent the most significant barrier to clinical translation. The chromosomal abnormalities observed in all embryos created through this technique would likely prevent healthy development if implantation were attempted.

Additionally, questions remain about whether the reprogrammed genes from skin cells can properly sustain embryonic development. As the study authors noted, in some cases the genes may still be activating as if they were in skin cells rather than early developmental cells.

Long-Term Developmental Risks

Even if embryos with normal chromosome numbers can be reliably produced, researchers would need to ensure that epigenetic programming—the chemical modifications that regulate gene activity—is correctly established. Improper epigenetic programming could lead to developmental problems later in life.

Extensive testing in animal models would be necessary to evaluate long-term health outcomes before any human clinical trials could be considered.

Global Reaction and Expert Commentary

The scientific community has responded with a mixture of enthusiastic optimism and cautious reservation, acknowledging the significance of the breakthrough while emphasizing the substantial work still required.

Prof. Amander Clark, a professor of molecular and developmental biology at UCLA who was not involved in the research, provided measured praise: “It’s unclear whether skipping meiosis in half the genome is compatible with human development. Time and more fundamental research will tell”.

Prof. Ying Cheong, a professor of reproductive medicine at the University of Southampton, described the work as an “exciting proof of concept,” noting that “in the future it could transform how we understand infertility and miscarriage, and perhaps one day open the door to creating egg- or sperm-like cells for those who have no other options”.

Prof. Richard Anderson of the University of Edinburgh highlighted the potential clinical impact: “Many women are unable to have a family because they have lost their eggs, which can occur for a range of reasons including after cancer treatment. The ability to generate new eggs would be a major advance”.

The research has also sparked important conversations about ethical governance of emerging reproductive technologies. Prof. Roger Sturmey of the University of Hull emphasized that “breakthroughs such as this impress upon us the need for robust governance, to ensure accountability and build public trust”.

What This Means for the Future of Fertility

Reshaping Reproductive Medicine

This breakthrough represents a potential paradigm shift in how we approach human reproduction and infertility treatment. If successfully refined and approved for clinical use, the technology could:

• Provide an alternative to egg donation for women without viable eggs
• Eliminate the need for invasive egg retrieval procedures in IVF
• Significantly extend the female reproductive lifespan

Offer new options for preserving fertility before medical treatments that might compromise reproductive function

Projected Timeline

Researchers estimate that it will take at least a decade of additional research before this technique could be deemed safe and effective enough to advance to clinical trials, assuming such trials would be permitted.

Other teams are pursuing different approaches to creating human gametes in the lab. Prof. Katsuhiko Hayashi, a developmental geneticist at the University of Osaka who has pioneered IVG research in mice, estimates that viable lab-grown human sperm could be about seven years away, with eggs potentially following a similar timeline.

The California-based startup Conception Biosciences is also working on developing lab-grown eggs, with CEO Matt Krisiloff suggesting that in a best-case scenario the technology could be “in the clinic within five years, but could be longer”.

Evolving Regulatory Landscape

As the science advances, regulatory frameworks will need to evolve accordingly. The Nuffield Council on Bioethics has recommended that scientists, ethicists, policymakers, and regulators work together to carefully consider the implications of this technology before clinical applications are considered.

Public engagement will be crucial in shaping policies that balance potential benefits against ethical concerns, ensuring that societal values are reflected in how these powerful technologies are governed.

The Core Science: A Step-by-Step Breakdown (The “How”)

Step 1: Reprogramming – Turning Back the Cellular Clock

Imagine every cell in your body like a worker with a very specific job. A skin cell, for example, is like a construction worker—it knows how to build and repair the “walls” of your body but can’t suddenly become a teacher or a chef.

How Scientists Grew Egg Cells From Human Skin: Scientists start by taking a small skin sample, usually made up of cells called fibroblasts. Using a special set of biological “instructions” (reprogramming factors), they turn back the cellular clock.

In other words, they erase the skin cell’s memory and return it to a “blank slate” state, just like restoring a computer to its factory settings. These reset cells are called induced Pluripotent Stem Cells (iPSCs)—cells that can become almost any other cell type in the body.

Step 2: Differentiation – Guiding the Cells’ Career Path

Once scientists have these blank-slate iPSCs, they need to teach them what to become next.

Through carefully timed doses of chemical signals—like giving career advice—they nudge the cells toward a new identity: primordial germ cell-like cells (PGCLCs).

You can think of this like guiding students in a career fair. At first, they could be anything—doctors, artists, engineers—but then they’re gradually directed toward a specific field. In this case, the cells are guided toward becoming the earliest versions of reproductive cells—the precursors to eggs and sperm.

Step 3: Maturation – Finishing School for Egg Cells

The final stage is the most complex and delicate. These precursor cells still need the right environment to fully mature into functional oocytes (egg cells).

To achieve this, scientists often grow them alongside ovarian tissue cells, which act like mentors or a nurturing classroom. These surrounding cells provide the proper biological cues—nutrients, hormones, and signals—that help the egg cells complete their development.

FAQs About Lab-Grown Egg Cells

Can scientists really make human eggs from skin cells?

Yes, researchers at Oregon Health & Science University have successfully Grew Egg Cells From Human Skin, as reported in a September 2025 study published in Nature Communications. However, the technology is still in early experimental stages and not yet ready for clinical use.

How does skin become an egg cell?

Scientists use a technique called somatic cell nuclear transfer, where they extract the nucleus from a skin cell and transplant it into a donor egg that has had its own nucleus removed. Through a process dubbed “mitomeiosis,” the reconstituted egg is stimulated to reduce its chromosome number from 46 to 23, creating a functional egg cell with the genetic material of the skin cell donor.

Could this help women with infertility?

Yes, if successfully developed for clinical use, this technology could potentially help women who are unable to produce viable eggs due to advanced age, medical treatments like chemotherapy, or genetic conditions. It could provide them with genetically related eggs for use in IVF.

What are the ethical concerns about lab-grown eggs?

Key ethical concerns include the potential for creating “designer babies” through embryo selection, unauthorized use of someone’s genetic material without consent, possibilities for unconventional genetic relationships (such as children with one or more than two genetic parents), and the need for appropriate regulation.

When will lab-grown eggs be used in fertility treatments?

Researchers estimate it will take at least a decade of additional research to ensure the technique is safe and effective enough for clinical trials. The process needs significant refinement to improve efficiency and reduce chromosomal abnormalities before it can be considered for human use.

The successful creation of human egg cells from skin cells

The successful creation of human egg cells from skin cells represents a remarkable milestone in reproductive science, demonstrating what study author Shoukhrat Mitalipov described as achieving “something that was thought to be impossible”. This breakthrough offers hope to millions worldwide who struggle with infertility, while simultaneously raising profound ethical questions that society must address.

While the research is currently at a proof-of-concept stage with significant efficiency and safety limitations, it provides a compelling glimpse into a future where biological parenthood could be possible for those who currently have limited options. The potential applications—from treating age-related infertility to enabling same-sex couples to have genetically related children—highlight the transformative power of this technology.

As Prof. Stephen Wilkinson, Distinguished Professor of Bioethics at Lancaster University, aptly noted, “Before any application in human reproduction is considered, however, it is essential that there is a thorough, well-informed debate about any ethical, legal, or policy implications”.

The path from laboratory discovery to clinical application will be long and complex, requiring not only scientific refinement but also careful consideration of the moral dimensions of creating human life in novel ways. What remains clear is that this breakthrough has opened a new chapter in reproductive medicine, one that holds both extraordinary promise and significant responsibility.