The advent of CRISPR-based gene editing has reopened ethical questions many had assumed were (0) SETTLED (SETTLE). The prospect of eliminating 1HEREDITY diseases that have plagued families for generations is genuinely tantalising, and in several cases conditions previously considered 2CURE only through lifelong management now appear potentially treatable at their source. When the techniques are applied to 3EMBRYO cells, however, the ethical stakes rise sharply, since changes made at that stage propagate to all future descendants. Most scientific bodies have issued 4CAUTION statements urging restraint, and 5ETHIC widely argue that even benign-looking 6INTERVENE set precedents whose implications are hard to foresee. The distinction between therapeutic corrections and cosmetic 7MODIFY may prove blurrier in practice than in principle, and a permissive regulatory posture could, in retrospect, look gravely 8REGRET.