CRISPR–Cas9 is a gene-editing tool of great potential, although not necessarily from a disability-rights perspective (see D. J. H. Mathews et al. Nature 527, 159–161; 2015). People with disabilities are, in my view, unlikely to be queuing up for genetic modification: their priority is to combat discrimination and prejudice.

To 'fix' a genetic variation that causes a rare disease may seem an obvious act of beneficence. But such intervention assumes that there is robust consensus about the boundaries between normal variation and disability. Contrary to the prevailing assumption, most people with disabilities report a quality of life that is equivalent to that of non-disabled people (G. L. Albrecht and P. J. Devlieger Soc. Sci. Med. 48, 977–988; 1999).

The UK Nuffield Council on Bioethics is deliberating the ethical and social dimensions of CRISPR. International guidelines are urgently needed (Nature 526, 310–311; 2015), and the voices of people living with illness and impairment need to be heard.