Breakthrough: mitomeiosis creates eggs from skin cells
A US team has published a pioneering study describing a proof‑of‑concept approach that could one day allow infertile people to have biological children. Using a technique dubbed mitomeiosis, researchers turned DNA taken from a skin cell into a functional human egg, which was subsequently fertilised with sperm in the laboratory. A small number of fertilised eggs survived to day six, roughly the stage at which embryos are usually prepared for implantation in IVF.
The results were reported in Nature Communications and have sparked both cautious optimism and questions about the road ahead before this could become a clinical option for people seeking to start a family.
What is mitomeiosis and how does it work?
The team sought to blend two fundamental modes of cell division found in humans: mitosis (the routine division that copies cells) and meiosis (the specialized division that creates eggs and sperm with half the usual number of chromosomes). By removing the nucleus from a donor egg and replacing it with the donor skin cell’s DNA, they redirected the cell division pathway to produce an egg with the correct 23 chromosomes. This “hijacking” of the cell’s machinery allowed the transformed egg to be fertilised by sperm in the lab.
The researchers reported creating 82 eggs from the skin DNA and fertilising them. Nine per cent of these fertilised eggs developed to the blastocyst stage, the point at which the embryo would normally be implanted in IVF.
Interpreting the numbers: what 9% means
While 9% reaching the blastocyst stage may seem modest, it is important to compare it with typical IVF success rates at early stages, which can be higher or lower depending on the clinic and patient factors. The researchers noted that the embryos progressing to blastocyst largely contained 23 chromosomes, but many did not split as expected during development, suggesting chromosomal missegregation was a common hurdle. This highlights that, although the concept is promising, the process is far from reliable enough for clinical use at present. The team is actively investigating how chromosomes pair and separate during normal egg development to improve the accuracy of this approach.
Implications for infertility and genetic parentage
The technique is framed by its potential to help people with few or no eggs or sperm to have a biological child. In particular, the study raises the possibility that DNA from individuals of the same sex could be used to create a child genetically related to both partners in the future. This could, in theory, enable same‑sex couples to have a child with genetic ties to both parents. However, such possibilities remain speculative and ethically complex, with safety and regulatory considerations dominating the near‑term outlook.
How does mitomeiosis compare with IVG?
Mitomeiosis sits alongside another line of research known as in vitro gametogenesis (IVG). IVG attempts to revert ordinary cells to a stem cell state and then reprogram them into eggs or sperm. Proponents say IVG could be slower to clinical application due to the complexity of reprogramming and differentiation, while mitomeiosis claims a potentially faster path by leveraging existing egg‑like development mechanisms. Regardless of the approach, both strategies aim to produce reproductive cells from non‑reproductive tissue, with IVF as the ultimate target step in turning those cells into a child.
Next steps and scientific hurdles
Experts emphasize that much work remains. The current experiments show early development, not a clinically ready protocol. A major challenge is ensuring correct chromosome pairing and segregation across all eggs and embryos to avoid abnormalities. The researchers are intensifying studies of meiosis and chromosomal behavior to refine the technique and improve efficiency and safety before any clinical trials could be contemplated.
Ethical and regulatory considerations
Ethics and law are central to any move toward using this technology in humans. While many jurisdictions permit research on surplus IVF embryos, transforming somatic cells into eggs or sperm and creating embryos could fall into a different regulatory category. Experts caution that extensive human-cell trials, robust oversight, and thoughtful policy development will be essential to address potential harms, consent, and the long‑term welfare of children who might be born through such methods. The legal landscape differs between countries, underscoring the need for broad, informed discussion among scientists, ethicists, policymakers, and potential prospective parents.
Conclusion: a cautious step forward
The mitomeiosis approach marks a notable advance in reproductive biotechnology, offering a new lens on how eggs might be produced from non‑reproductive tissue. Yet the journey from laboratory proof‑of‑concept to a safe, ethical, and accessible clinical option is long and uncertain. Researchers, clinicians, and regulators will need to work together to navigate the scientific, ethical, and legal complexities as this field evolves.
