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Will same-sex couples soon be able to conceive their own child? Yes, according to a new study. A Japanese researcher has indeed succeeded in creating eggs from male mouse cells.
Research around human gametogenesis continues to expand. Recently, a Japanese researcher succeeded in the impossible: to create eggs from male mouse cells. If this technique could one day be used for infertile or same-sex couples, a moral question arises. The results, presented on March 6, 2023 during the international summit on human genome editinghave been submitted for publication in the scientific journal Nature.
A stem cell “programmed” to become an egg
The author of this work, Professor Katsuhiko Hayashi of Osaka University, used mice to carry out his research. Concretely, he took a skin cell from a male mouse, then transformed it into a stem cell (the “mother” cells from which all other cells develop).
The professor then deleted the Y chromosome, duplicated the X chromosome, and then fused the two Xs together. This adjustment allowed the stem cell to be “programmed” to become an egg. Finally, the cells were cultured in an ovarian organoid, a culture system designed to replicate the conditions inside a mouse ovary.
When these created eggs were fertilized with normal sperm, scientists obtained around 600 embryos. All were implanted into surrogate mice, resulting in seven pups. The efficiency (about 1%) was lower than that obtained with normal eggs, where about 5% of the embryos went on to produce a live birth.
Healthy baby mice
The baby mice appeared healthy, had normal lifespans, and had offspring as adults.
“They look good, they seem to grow normally, they become fathers“, said Hayashi.
“This is the first case of making mammalian oocytes from male cells.“, assured Professor Katsuhiko Hayashi, during the summit taking place within the Francis Crick Institute in London.
He and his colleagues are now trying to replicate the creation of lab-grown eggs using human cells.
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Ethical reservations and a technique to be improved
This technique could be usedwithin a decade“to infertile couples in which the women are unable to make their own eggs, but the author pointed out that it is far from complete.
“Even in mice, there are many egg quality problems. So, before we can consider it as an infertility treatment, we have to overcome these issues, which could take a long time.“, did he declare.
Professor Hayashi further clarified “that he would not be in favor of this technique being used by a man to create a baby“using his own sperm.
“Technically it is possible. But I don’t know if at this point it’s a safe or socially acceptable practice.”.
An observation shared by Professor Haoyi Wang, of the Chinese Academy of Sciences.
“Scientists never say “never” because in principle it was possible in mice, so of course it may be possible in humans, but I think there are still a lot of challenges ahead and I don’t could predict how many years it would take“.