Professor Li Jinsong’s team in China has succeeded in producing large quantities of “good quality” artificial sperm from mice.
In 2012, the same team published similar results but “the quality of the spermatozoa posed a problem”.
They improved their technique with the CRISPR-Cas9 tool, which enabled them to modify several genes in the nucleus of the spermatozoa. They produced “semi-cloned” mice with a success rate of 20% compared to 2% in earlier experiments.
Their results were published in the Stem Cell journal. This research was carried out with the Shanghai Institute for Biological Sciences and the Chinese Academy of Science.
This study has raised new questions. To date, the scientists have carried out their experiments using murine embryos but other Chinese clinical trials have used the CRISPR-Cas9 tool on human embryos. Professor Li declared that this method for the “mass production of artificial sperm”would lead to an “ethical crisis” if it were applied to man.