Scientists at Osaka University have achieved a breakthrough in assisted reproduction by creating seven mice that have two biological fathers. Researcher Katsuhiko Hayashi used a genetic manipulation technique to produce female eggs (oocytes) from male cells, and successfully fertilized them. While the discovery has yet to be validated, in the long run it could open up new possibilities for reproduction, the study authors say.
To create the oocytes, the scientists used skin cells from male specimens and reprogrammed them into pluripotent stem cells, capable of transforming into any other type of cell. They eliminated the Y chromosomes from the cells and duplicated the X chromosomes, causing them to transform into oocytes with two X chromosomes. In summary: children from two biological fathers. Hayashi, first author of the research, he told the BBC that this technique could also be used in humans within a decade.

Assisted reproduction by two biological fathers: the doubts of the scientific community
It will take some time before the technology is ready to be used safely in humans. And I'm not referring to the ten years Hayashi talks about, who thinks from a purely scientific perspective. Human reproductive cells are very complex and less well known than those of mice, but the goal is within the reach of scientists. The point is another: doubts of an ethical nature must be overcome, and above all it is necessary to demonstrate that the technology is safe for use.
In any case, these results just obtained by the University of Osaka open a real new "strand" of research in the field of fertility and conception. This technology could inspire new studies and new possibilities also in human reproduction, increasingly in danger for a complex of factors that are still not entirely clear.