Though most men naturally have one testicle that is slightly larger than the other, sometimes the difference in size indicates an underlying cause, such as a spermatic cyst, hydrocele, epididymitis, orchitis or varicose veins, explains Go Ask Alice. Testicular cancer is a possible cause for a larger testicle. Another possible cause for one testicle being larger than the other is testicular torsion, according to Healthline.
Torsion of testes occurs when the spermiatic cord that carries blood to the scrotum twists, affecting blood flow to one or both testicles, reports Healthline. Testicular torsion rarely occurs in both testicles. The affected testicle experiences pain and swelling, which causes a difference in size. Men who have one testicle that occasionally hurts and is significantly larger than the other should visit a health care provider as soon as possible, advises FamilyDoctor.org.
Because many possible causes of differently-sized testicles threaten fertility or other permanent damage, men who notices any change in the size or appearance of his testicles should consult a health care provider, recommends Go Ask Alice.
Usually, the difference in size between the two testicles is about 1/2 a teaspoon, claims FamilyDoctor.org. In most men, the right testicle is slightly larger than the left.