Gene editing technologies including CRISPR-Cas9 are being applied to farm animals, disease research, and conservation. The welfare implications — both positive and negative — require careful ethical evaluation.
Gene editing presents a genuine welfare dilemma. On the positive side, resistance to diseases that cause chronic suffering in farmed animals, elimination of the need for painful surgical procedures like dehorning, and potential eradication of parasites from conservation populations represent meaningful welfare improvements. On the negative side, edited animals may carry unintended consequences — reduced immune function, metabolic problems, or developmental abnormalities — that create new welfare harms. The history of selective breeding for production traits (fast-growing broilers, high-yield dairy cows) shows that productivity-focused genetic modification reliably creates welfare harms. Welfare assessment of gene-edited animals requires long-term monitoring beyond standard regulatory timelines, including assessment of subtle behavioural and physiological indicators.