I prefer "testicular fortitude". It's not the strength of the organ, it's that the organ is where our strength comes FROM.

there's a great sex and the city episode called "the power of female sex". amidst a host of yonnic immagery and punning there is a sub-plot about a famed artist who has decided that the only thing worth painting anymore are expressionistic renderings of the vagina. he makes some quote akin to "there is nothing more powerful than the c*nt, it is the source of all human life" and go on to say how the world's population is controlled by it because all are connected to it maternally and/or sexually.