What is the reason for a large testicle and a small testicle

The testicle shows a big one small, involving the following reasons: first of all, physiological factors, physiological factors caused by a big one small testicle, the difference between the two is not big. Both may be their own sensory cognitive errors, but also may be the existence of objective reality, do not take special treatment, generally will not affect the normal body function. The second is pathological reasons, pathological reasons caused by a large testicle a small, it is likely to show hydrocele, need timely drug treatment or surgery.