Scientists have transformed skin cells into human eggs in an early-stage experiment that could one day offer new fertility options for older women and same-sex male couples.
The research, led by Prof Shoukhrat Mitalipov at Oregon Health and Science University, uses a technique similar to that which created Dolly the sheep. Skin cells were stripped of their nuclei and placed into donor eggs that had their own nuclei removed.
The resulting eggs were fertilised with sperm, but most failed to develop normally. Out of 82 eggs, fewer than 10% reached the stage at which IVF embryos are typically transferred, and none survived beyond six days.
Prof Mitalipov called the work a "proof of concept" and said perfecting the technique and proving its safety could take another decade. The main challenge is getting the correct number of chromosomes, as healthy eggs contain only 23, and the process produced random pairings.
Other scientists welcomed the study but stressed caution. Prof Richard Anderson of the University of Edinburgh said the ability to generate new eggs would be a major advance, but important safety concerns remain. Prof Ying Cheong of the University of Southampton said it could transform understanding of infertility and miscarriage.
