Nat. Biotechnol. 35, 1029–1042 (2017); published online 9 November 2017; corrected after print 10 November 2017

In the version of this article initially published, J.E. Lunshof's affiliation was given as “Center for Bioethics, Harvard Medical School, Boston, Massachusetts, USA”; the affiliation should have included her main affiliation at the University of Groningen and read, “Department of Genetics, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands, and Department of Genetics, Church laboratory, Harvard Medical School, Boston, Massachusetts, USA.” In addition, “Divinity School, University of Chicago,” should be “University of Chicago Divinity School.” The errors have been corrected in the HTML and PDF versions of the article.