Why would my left testicle be half the size of my right testicle?

Last updated on August 27, 2020


My left testicle is almost half of the size of my right testicle. Is this a problem for me, or should I consult a doctor?


It is typical for a man’s testicles to be slightly different sizes. This is especially true when you are growing as one side can grow sooner than the other side. But a large difference in size indicates a problem. I just want to warn you up front that the doctor can often fix the problem, but it won’t change the size of testicles.

Some common causes are:

  • Torsion when you were younger that damaged one testicle. Torsion is when a testicle twists on its cord and cuts off the blood supply to the testicle. Without the oxygen in the blood, the testicle dies or might be severely damaged.
  • A varicocele or hydrocele may be making one testicle appear to be larger than it is. Your veins have small valves in them to keep blood moving in one direction. If a valve is damaged, the blood will pool and swell the vein (called a varicocele). Your scrotum also has fluid in the sac to protect the testicles, but again a valve can fail causing swelling (called a hydrocele). These are mildly to significantly painful. They are repairable and need to be done since either can damage a testicle.
  • Though rare, cancer can make a testicle bigger than it should be. Testicular cancer is hard and deforms the smooth oval shape of a testicle. It usually is not painful. This can be treatable if caught early.
  • An infection can cause temporary swelling of one testicle. Some infections, such as mumps, can permanently damage a testicle so that it won’t grow when you develop.


Thank you very much for your quick response. May God bless you. I want to provide you with more details about my condition regarding my testicles.

I have noticed many years ago the uneven size of my testicles, but there is no pain in my testicles and there is no fluid forming in my testicles’ cover (which contains the two testicles. Sorry, I don’t know the specific name of it). The left testicle is half of the size of the right one. I am living a regular life. Next year I am going to get married. Is it going to affect my married life? If I don’t consult a doctor, what will happen? How far is it serious? Please help me.

What kind of doctor should I consult?


The sack containing your two testicles is called the scrotum.

The difference in your testicles size hints that you had damage to one of your testicles a long time ago. The most likely cause is having mumps when you were younger. There is nothing that can be done about that, such damage is permanent. This won’t affect your married life since one testicle by itself is able to supply plenty of male hormones for your body and sperm to give you children.

You can see a urologist if you want to ensure that you are producing viable sperm, but wouldn’t be a necessity except for your peace of mind.


Thanks for your concern. I understand that the doctor cannot make the testicles the same size, but does having different size testicles mean there is a problem? Should I be worried even though I don’t have any pain and the size of the scrotum is OK? I am sure there is no fluid collecting in my scrotum.

I am worried about my sperm count. I hope I check out fine, but if the count is low, is it recoverable? I often masturbate three or four times a week. Is masturbation affecting my testicle size? A long time ago I did worked out in a gym, could the exercise have affected my testicles?

But I will visit a doctor soon and I’ll let you know the results.


Neither exercise or masturbation will effect a man’s testicle size.

It sounds to me that you have nothing to worry about. Yes, something (most likely a disease like mumps) damaged one of your testicles in the past. However, that is over with.

If your sperm count is low, it means it will be harder for you to have children, but not necessarily impossible. In theory, only one viable sperm is needed to fertilize an egg. The reason men ejaculate so many sperm is to increase the odds that one sperm will reach the egg at the right time. If you have a low sperm count, the question to be answered is “why” before it can be answered if something can be done about it. One testicle is able to provide more than enough male hormones for your body and sperm for fathering a child. Since you are ejaculating multiple times a week, it is clear your hormones are not low, so I would guess that the doctor will find that you have plenty of viable sperm in your ejaculations.