Scientists in the US have successfully created human eggs from skin cells in a breakthrough that could one day transform fertility treatment.
The early-stage research, led by Prof Shoukhrat Mitalipov at Oregon Health and Science University, offers hope to women unable to produce viable eggs due to age, illness, or treatments such as chemotherapy. The technique could also provide options for same-sex male couples to have genetically related children.
The work adapts cloning methods used to create Dolly the sheep in the 1990s. Researchers removed the nucleus — containing 46 chromosomes — from skin cells and inserted it into donor eggs with their own nuclei removed. The challenge was reducing the chromosome number to 23 so they could properly pair with sperm during fertilisation.
By fertilising the reconstructed eggs and activating them with a compound called roscovitine, the team triggered chromosome reduction. However, the process was not fully accurate: the chromosomes often segregated incorrectly, leading to embryos with abnormal genetic make-up. Out of 82 eggs created, fewer than 10% developed to the early embryo stage, and none were grown beyond six days.
Mitalipov described the work as a “proof of concept” and estimated it could take another decade to refine the technique for clinical use. Experts praised the potential but stressed safety and ethical considerations. Prof Richard Anderson of the University of Edinburgh said the ability to generate eggs would be a “major advance” for women who have lost theirs, while Prof Roger Sturmey of the University of Hull emphasised the importance of public dialogue and strong regulation.
Though far from clinical application, the research signals a future where lab-grown eggs might help many people — from older women to same-sex couples — achieve biological parenthood.
