Human eggs have been grown within the laboratory for the first time, say researchers on the University of Edinburgh.
The team say the method could lead to new ways of preserving the particular fertility of children having cancer therapy.
It is also a chance to explore how human eggs create, much of which remains a secret to science.
Professionals said it was an exciting breakthrough, yet more work was needed prior to it could be used clinically.
Women are born with premature eggs in their ovaries that can create fully only after puberty.
It has taken years of work, but scientists are now able to grow eggs to maturity outside the ovary.
It takes carefully controlling laboratory conditions which includes oxygen levels, hormones, proteins that will simulate growth and the medium where the eggs are cultured.
But while the researchers have shown it is possible, the approach released in the journal Molecular Human Duplication still needs refinement.
It is very inefficient with only 10% of eggs completing their trip to maturity.
And the eggs have not been fertilised, so it is uncertain how viable these are.
Prof Evelyn Telfer, one of the researchers, told the BBC: “It’s very exciting to obtain evidence of principle that it’s possible to reach this phase in human tissue.
“But that has to be tempered with the whole lot of work needed to enhance the culture conditions and test the standard of the oocytes [eggs].
“But apart from any scientific applications, this is a big breakthrough within improving understanding of human egg growth. ”
The process is very tightly managed and timed in the human body : some eggs will mature throughout the teenage years, others more than 20 years later.
A good egg needs to lose half the genetic material during development, or else there would be too much DNA when it has been fertilised by a sperm.
This excess is cast away into a miniature cell called the polar body, but in the study the particular polar bodies were abnormally huge.
“This is a issue, ” said Prof Telfer. However it is one she thinks can be tackled by improving the technology.
Work on mouse eggs, that was nailed 20 years ago, showed the particular technology could be used to produce reside animals.
Complementing this achievement in human cells could eventually be used to help kids having cancer treatment.
Chemotherapy and radiotherapy dangers making you sterile.
Women can freeze matured ovum, or even embryos if they are fertilised having a partner’s sperm, before starting treatment — but this is not possible for girls along with childhood cancers.
Right now they can have ovarian tissue frosty before treatment, which is then bring back in to mature years later when the patient wants children of their own.
But if there are any kind of abnormalities in the frozen sample after that doctors will think it is too dangerous.
Being able to create eggs in the lab would be a more secure option for those patients.
Mr Stuart Lavery, the consultant gynaecologist at Hammersmith Medical center, said: “This work represents an authentic step forward in our understanding.
“Although still in small quantities and requiring optimisation, this initial work offers hope for patients. inch
It would be legal in order to fertilise one of the lab-made eggs to generate an embryo for research reasons in the UK.
But the group in Edinburgh do not have a license to carry out the experiment. They are talking about whether to apply to the embryo power for one, or collaborate with a center that already has one.
Prof Azim Surani, the director of germline analysis at University of Cambridge’s Gurdon Institute, said: “Molecular characterisation plus chromosomal analysis is needed to show exactly how these egg cells compare with regular eggs.
“It might be of interest to test the developing potential of these eggs in lifestyle to blastocyst stage, by trying IVF. ”
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