For CRISPR to gradually move into germline editing, we need to understand how the tool interacts with cells during early human development.

Rebecca Lea and Dr. Kathy Niakan at the Human Embryo and Stem Cell Laboratory at the Francis Crick Institute in London, UK, laid out those challenges in a sweeping article in Nature. CRISPR as a gene editor is getting more specific and efficient by the day, they explained. However, for it to gradually move into germline editing, we also need to understand how the tool tangos with cells during early human development.
— Read on singularityhub.com/2019/12/12/how-far-are-we-from-accurately-and-safely-editing-human-embryos/