grow a pair

Etymology
Abbreviation of "grow a pair of testicles".

Verb

 * 1)  To be brave; to show some courage, especially in a situation in which one has so far failed to do so.

Usage notes
Occasionally used in reference to women.
 * It's ironic because this backlash came the same week of our Katie Couric cover story — which prompted an outpouring of ... The Times wrote that Couric came off as freer about her frustration, while Salon told Couric to grow a pair.

Translations

 * German: lass dir Eier wachsen, lass dir ein Paar Eier wachsen