The group of LI Jinsong from CAS SIBS in Shanghai promoted cell division of a mature egg through chemical means and created a line of cells. After modifying one cell by removing two genes, they injected the cell into another egg as part of artificial fertilization process. More than 15 out of 100 embryos finally developed into mice which were healthy and showed no difference in development and fertility from the ones that were naturally conceived. Attempts to create embryos from two sperm cells failed.
CAS news release, November 20, 2015