Genome editing on human embryos by crispr is attractive but controversial

CRISPR/Cas9 is a powerful tool for the genome editing of nearly all species, including rodents, zebrafish, non-human primates and humans, both ex vivo and in vivo. The experiments conducted on embryos (or gametes) show many advantages including high cutting efficiency and homology-directed repair (HDR) rates, easy manipulation and screening, compared with those on somatic or pluripotent cells. In this chapter, some successful works correcting gene mutations in human embryos are described. However, safety and ethic concerns are the main factors hurdling its clinical promotion before we find the perfect solutions to mosaicism and off-target mutagenesis. Some scientists suggested that we should not open this "Pandora's box" until we make a list of the goals to be achieved by CRISPR-based embryo editing. Shortly, talks among researchers, ethicists, business leaders, and maybe the public, will be the final way to the answer.