The Japanese researchers say the success rate remains very low and no human experiments are planned yet.
In Japan, the work of researchers raises an astonishing question: do we still need women to make babies? The answer is even more surprising: maybe not. Japanese researchers have just succeeded, for the first time, in generating a few baby mice that have two dads and no mom. They are now wondering if this revolutionary technique could not be applied to humans.
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The results of their work have just been published in the scientific journal Nature and, already, many foreign experts assure that this research, made in the universities of Kyushu and Osaka is quite revolutionary. But also very disturbing.
Mice have the same genetic sex determination system as humans. Male mice – like men – have XY chromosomes, while female mice have XX chromosomes. It is the same in all mammals. Male and female gametes meet and bring their different chromosomes. The challenge for the Japanese researchers was to see if they could create from male cells, which carry the XY chromosome, female cells which carry the XX chromosome.
Birth of baby mice
After years and years of experiments, they managed to create, from male mouse cells, an egg carrying the female chromosome XX. They actually took small pieces of cells taken from the tails of male mice and processed them to turn them into what are called pluripotent stem cells. It is a type of cell that is studied a lot in regenerative medicine.
During this reprogramming, some cells lost their Y chromosome, which gives the male character, to have only X. And after duplication, scientists managed to create the same XX chromosome, which is found in females. They then created an egg carrying this XX chromosome. They fertilized it with sperm from a male mouse. The meeting worked and baby mice were born.
No experience expected in humans
These babies are healthy, but the experiment rarely works. They managed to give birth to only 7 baby mice for 630 trials, or 1% success. At the moment, no experiments are planned with humans, but the researchers say it could be technically feasible in the future.
This could even be, in the long term, a possible solution for couples who have fertility problems or for a couple of men who would like to have a child. On the other hand, the researchers say themselves that there is a difference between what we know how to do and what must be done. They are based in particular on the success rate which, for the moment in mice, is not at all satisfactory.
Their experiments also raise major ethical questions. They believe that society, public opinion will have to debate this subject for years before anything is attempted with humans.