CRISPR-Cas9 technology can be used to edit any gene in any organism without limitations or potential consequences.

CRISPR‑Cas9 lets scientists cut DNA at a chosen spot, but it does not work on every gene in every organism without problems. The enzyme can miss the target or cut elsewhere, causing unwanted mutations, and delivering the CRISPR components into cells or whole organisms can be technically difficult. Even when a gene is edited correctly, the change can have unforeseen effects on the organism’s biology or raise ethical questions about altering living beings. For example, cutting the CCR5 gene in a human stem cell can make cells resistant to HIV, but it also removes a protein that has other roles in the immune system, showing that consequences must be carefully evaluated.