The concept of genome-editing has revolutionised the field of Basic Biology research, medicine and biotechnology. The technologies, through DNA-binding protein, are engineered to cause modification of specific genes. In the process, carry out the needed repair of the selected mutant genes. As a result, it could offer treatment modalities to some diseases afflicting humans. However, the safety profile of the technology only guaranteed with the somatic cells. Recently, a new editing tool clustered regularly interspaced short palindromic repeat (CRISPR)-associated system (Cas) now available. The fact that CRISPR-Cas uses RNA molecules with some degree of human DNA sequence specificity has brought about an attempt at extending its use in the human preimplantation embryo. This consideration has generated serious concern bore out of the poor knowledge of the mechanism of DNA repair in the human preimplantation embryo. As a result, the possibility of off-target, mosaicism could portend catastrophic effect on the future generation.