Japanese scientists have managed to create mice with two biological fathers

Japanese scientists have managed to create mice with two biological fathers. This breakthrough opens up radically new possibilities for infertility treatment, and gives same-sex couples hope to have a common biological child, SkyNews reports.

The achievement was announced at the Third International Summit on Human Genome Editing at the Francis Crick Institute in London by biologist Katsuhiko Hayashi, known for his work in the field of growing eggs and sperm in the laboratory.

Together with colleagues at Kyushu University, the scientist managed to transform skin cells carrying a male combination of XY chromosomes into an egg with a female version of XX. To do this, male skin cells were reprogrammed into so-called induced pluripotent stem cells. Then the Y chromosome of these cells was removed and replaced with an X chromosome taken from another cell. The result was iPS cells with two identical X chromosomes.

The resulting cells were cultured in an ovarian organoid, the conditions in which reproduce the conditions inside the mouse ovary. The eggs were fertilized with sperm, and about 600 embryos were implanted into surrogate mice. As a result, seven mice were born, all of them were healthy, had a normal life expectancy, and when they grew up, they had their own offspring.

Now Hayashi and his colleagues are trying to repeat this success using human cells. According to the scientist, it is possible to do this within the next decade. Although this practice may raise questions from the point of view of safety: in humans, eggs grow more slowly, and there is a possibility that cells acquire undesirable mutations. Also, such a method could help in the treatment of severe forms of infertility, for example, in Turner syndrome, when women lack or partially lack one copy of the X chromosome.