In a remarkable milestone, researchers have grown human eggs from their earliest stages to maturity in a laboratory for the very first time. The achievement offers a future for women at risk of infertility, either through illness or medical treatment, to be able to store immature eggs for later fertilization.

Building on 30 years of research, this achievement outlines three fundamental steps that successfully took ovarian tissue samples and nurtured them into human eggs to a point of full maturity. It is not clear how healthy the final eggs produced are as the speed of maturation in the lab was significantly faster than it would occur in the human body.

"Being able to fully develop human eggs in the lab could widen the scope of available fertility treatments," explains Evelyn Telfer, lead on the research. "We are now working on optimizing the conditions that support egg development in this way and studying how healthy they are. We also hope to find out, subject to regulatory approval, whether they can be fertilized."

Much more work needs to be done before this breakthrough leads to any clinical applications, and while many researchers recognize the milestone achievement, they also suggest there are many important questions yet to be answered.

"The technology remains at an early stage, and much more work is needed to make sure that the technique is safe and optimized before we ascertain whether these eggs remain normal during the process, and can be fertilized to form embryos that could lead to healthy babies," says Ali Abbara, an endocrinologist from Imperial College London who didn't work on this new study.

Additionally, the researchers say insights into the development of human eggs at various stages provided by the study could help research into other infertility treatments.

The new research was published in the journal Molecular Human Reproduction.

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