In 1924, motivated by the rising eugenics movement, the United States passed the Johnson–Reed Act, which limited immigration to stem “a stream of alien blood, with all its inherited misconceptions”. A century later, at a campaign event last October, now US President Donald Trump used similar eugenic language to justify his proposed immigration policies, stating that “we got a lot of bad genes in our country right now”.

If left unchallenged, a rising wave of white nationalism in many parts of the globe could threaten the progress that has been made in science — and broader society — towards a more equitable world1.

As scientists and members of the public, we must push back against this threat — by modifying approaches to genetics education, advocating for science, establishing and leading diverse research teams and ensuring that studies embrace and build on the insights obtained about human variation.