“Reproductive biology: Progesterone's gateway into sperm” by Steve Publicover and Christopher Barratt (Nature 471, 313–314; 2011). The following sentence in this article — “The second, more recent, advance was the development of a method for applying to sperm the technique of whole-cell patch clamping, which records ionic currents across the entire plasma membrane of a cell” — should have been accompanied by a reference to P. V. Lishko, I. L. Botchkina, A. Fedorenko & Y. Kirichok Cell 140, 327–337 (2010).