well, there is an obvious answer to this question.  Heres how you figure out which nut to loose:
step 1: Have a beer, this may depress you
step 2: imagine yourself without a left nut, think of all the times you have spent with it and cherished it
step 3: repeat step 2 but for the right nut
step 4: have another beer, its depressing to think about losing a nut
step 5:
step 6:  imagine yourself with no nuts, what do you feel?
step 7: think of step 5 again, and come to a conclusion.
You have now become aware that loosing a testicle is out of the question. Who ever the fvck is trying to get rid of one, shoot him in the face