Scientists have claimed to have grown mature human sperm in test tubes in a breakthrough that could help combat male infertility.
The sperm cells, which have been developed for the first time in a “bioreactor” in a laboratory, are said to look identical to those produced naturally.
And according to the scientists at a research institute in Lyon, France, the technology could be ready within up to four years to help men who are unable to make their own sperm have their own biological children.
However, sceptics have expressed doubts, claiming the findings should not be verified until the research is published in a peer-reviewed journal.
A team led by Phillippe Durand, scientific director of biotechnology start-up Kallistem, claimed to have taken immature germ cells from the testes of six men who were infertile and developed them in a bioreactor.
“We have completed spermatogenesis – the production of mature sperm cells – in vitro using a bioreactor. We have done it in three different species, rat, monkey and human, which has never been done before,” The Independent on Sunday reported.
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“It is not possible to discuss details of the research as we have just submitted our study for publication a few days ago, but we have produced a meaningful amount of mature sperm that could be of use clinically,” he added.
Scientists have been searching for a way to produce human sperm that could fertilise human eggs in a test tube for the past 20 years – but with no success.
Allan Pacey, professor of andrology at Sheffield University, said the French scientists had made a “bold claim”.
“Until I’m able to see the published research I’m deeply sceptical,” he said. “If they have a scientific paper in press, why not wait until it’s published before going public?
“The picture of the sperm they have published is not convincing. It doesn’t look like a mature sperm to me, but an elongated cell. The only decent thing for the science and for the public is for them to show us all the evidence.”
However, Institut de Génomique Fonctionnelle, where the latest development was made, said the breakthrough was genuine and that it could help the 15,000 young cancer patients around the world left sterile by chemotherapy and the 120,000 adult men whose infertility could not be treated by existing IVF procedures.
“This breakthrough opens the way for therapeutic avenues that have been eagerly awaited by clinicians for many years,” the institute said in a press statement.