Removing one testicle will have absolutely no effect on a man’s physical ability to get and maintain an erection. The remaining testicle will produce enough of the male hormone, testosterone, to keep the man’s erections just as normal as before the operation. Why would a man ever need to have both testicles removed? For two conditions: advanced prostate cancer and cancer in both testicles (an extremely rare condition).
Just as the healthy prostate depends on testosterone to keep functioning normally, prostate cancer needs testosterone to keep growing. In very advanced cases, the surgeon may recommend removing both testicles in order to get rid of the cancer’s source of growth, testosterone. (This is another incentive to have annual rectal examinations if you are over 40 years of age; the sooner prostate cancer is detected, the better it can be treated. Early detection and treatment almost always leaves a man with both testicles.)
If s extremely rare for a man to develop testicular cancer in both testicles, but it does happen on occasion. Unfortunately, removing the testicles (the major source of testosterone production) also takes away much of a man’s sexual desire. In this case, however, testosterone does not promote growth of the testicular tumors, so the hormone can be replaced with shots.
All of these potency-sapping medical problems are serious, and no man should try to diagnose and treat them on his own.