In a groundbreaking study published in Nature Communications, scientists at Oregon Health & Science University have, for the first time, created human eggs from skin cells. The work represents a proof-of-concept that could one day allow women who cannot produce viable eggs—due to age, medical treatment, or health conditions—to have genetically related children. It may also open new doors for same-sex couples. However, researchers caution that the technique is still in its early stage and far from being clinically applicable.
What the Researchers Did
- The team used somatic cell nuclear transfer (SCNT): they removed the nucleus from a human skin cell and inserted it into a donor human egg whose own nucleus had been removed.
- Because skin cells carry 46 chromosomes (23 pairs), unlike eggs which need only 23, an extra reduction step was needed. The scientists developed a process they call mitomeiosis, which mimics natural reproductive cell division by getting the egg to discard half its chromosomes.
- They produced 82 egg-like cells (oocytes) using this technique. These were then fertilised with sperm in the lab. Of those, about 9% developed to the early blastocyst stage after ~6 days.
Results & Limitations
- Many of the embryos showed chromosomal abnormalities: wrong numbers of chromosomes, incorrect pairings, or missing/extra chromosomes. This means most of them would not be viable for further development.
- None were cultured beyond the blastocyst stage; no attempt at implantation or pregnancy.
- Efficiency is low; success rates are small (≈9%) and there remain significant safety, ethical, and technical hurdles before any clinical use.
Why It Matters
- Infertility Treatment Potential: For women who have lost ovarian function or eggs (e.g. due to chemotherapy, age, genetic issues), this could eventually offer a way to use skin cells to generate eggs.
- Benefit for Same-Sex Couples: It raises the possibility that same-sex male couples might have a child genetically related to both partners, though that is far in the future.
- Scientific Insight: This demonstrates that non-reproductive cells (skin cells) can be reprogrammed and manipulated to undergo processes normally limited to germ cells (like meiosis and chromosome reduction) in lab settings.
Ethical, Safety, and Regulatory Considerations
- Chromosomal Errors & Safety Risk: The high rate of abnormal chromosome counts means immediate use in human reproduction is unsafe.
- Regulation & Oversight: Legal and ethical frameworks will need to evolve to address issues like embryo creation, consent, potential misuse, and genetic integrity.
- Long Timeline: Researchers estimate at least a decade of further work is needed before this could move toward clinical trials (if permitted). Reuters
Conclusion
While the achievement by the OHSU group marks a powerful scientific milestone—creating fertilisable human eggs from skin cells—the path to clinical application is long and fraught with challenges. For now, this remains a proof-of-concept. But its implications for infertility treatment, reproductive choices, and genetics are profound.
