Probably gay men are more aware of their bodies that straight men. For some weird reason it seems that men do not feel their own balls.
Why the heck not?
To me, it's daft. Since the balls are an integral part of erotic love play, whether sucked, fondled, squeezed gently, or simply stroked (yes I know there are more extreme things you can do to them, but that ain't for me!), then I just can't understand why men don't notice if their balls are "odd".
So, what should they be like?
Ovoid (Ok, egg shaped), firm (that means not rock hard, but not squidgy), regular shaped, linked by a tube to the internal workings, uniformly tender if squeezed too hard. What they will not be is the same size as each other.
Just rarely, one may be literally not connected by a tube. If you find this, check your medical records. It may be a prosthesis. Many reasons, but check the records. No need to be concerned. We only need one! Just makes comparison a lot harder!
What you are looking for as an early indicator of testicular cancer, is "oddness". This can be that one gets larger, suddenly, or at an alarming rate. It can be an odd texture. It can be that one even shrinks.
Risk making an embarrassed fool of yourself, and go to your doctor. He will, of course, need to fondle your balls. You may even get the old "up and under" prostate exam! Treat these as a major bonus if the doctor is attractive.
So check on a monthly schedule. Please. And don't worry of you even have to have both testicles removed. Hormone Replacement Therapy means that you won't be less of a man. And you can have a pair of prostheses for those "Shower Room Moments"!