Scientists have made a revolutionary discovery, publishing papers on Wednesday that detail the successful creation of a mouse with two fathers. The method is far from applicable to humans, as it has a low success rate, adaptability concerns, and ethical issues. This breakthrough could enable gay couples or single men to have a biological child without the need for a female egg.
The study, published in Nature, was conducted by a team of scientists in Japan under the direction of Katsuhiko Hayashi of Osaka and Kyushu universities. Hayashi and his colleagues had previously discovered a method to extract skin cells from female mice and turn them into eggs, which could be used to create healthy babies.
In their most recent research, the team removed tissue cells from male mice and used a dish to transform them into induced stem cells that can develop into any cell. Around six percent of the cells lost their Y chromosomes, leaving just an X-chromosome called XO. Then, with the help of a fluorescent protein and an antagonist called reversine, the researchers successfully replicated the X genome in the cells, creating the XX set.
These cells were used to fertilize eggs with sperm from a different male mouse before being implanted in the uteruses of female surrogate mice. Out of 630 attempts, seven mice were born, which is a success rate of just over one percent. The puppies did not display any abnormalities and were fertile.
Hayashi, who presented the results at the Third International Summit on Human Genome Editing in London, warned that many obstacles remain before this technology can be applied to humans. Nitzan Gonen, the laboratory director for determining sex in Israel’s Bar-Ilan University, called the paper “revolutionary” while noting that there is still a long way to go.
Theoretically, this technique could allow two males of the same gender to have a child, with one providing the sperm and the other the egg. Alternatively, one man might be able to provide both the sperm and the egg, which could be similar to cloning.
Jonathan Bayerl and Diana Laird, reproductive and stem cell experts from the University of California, San Francisco, said that it is still unclear whether the procedure could work with human stem cells. However, they called it “a milestone in reproductive biology.”
The report suggests that a possible application could be to save an endangered species with only one male left, provided that a female is from another species. However, Gonen noted that the process is currently “extremely inefficient,” with 99 percent of embryos failing to survive.
Gonen estimated that scientifically speaking, the technology could be available to humans within 10 to 15 years. However, she noted that this does not include the time needed to address any ethical issues that could arise.