In the January 2018 issue, the article “Puzzling over privilege: How the immune system protects—and fails—the testes” (Nat. Med. 24, 2–5, 2018) inaccurately listed an NIH workshop as having been held in September 2016. The workshop was held in September 2017. The error has been corrected in the HTML and PDF versions of the article as of 24 January 2018.