A simple (rather primitive) way of assessing the function of the testicles is to assess their size. Measuring the testicles has its obvious problems, but an examiner can feel them easily as they hang in the scrotum. An orchidometer is a string of oval balls of varying size from 25 cc. down to 1 cc. or less. The examiner gently feels the testicle with one hand while feeling the balls on the orchidometer with the other. It is amazing how accurately the size and volume of the testicle can be estimated by this method. If the testicle is found to be below normal size it may be diseased, particularly if there is a significant difference in size between the two testicles. An oversize testicle may also be abnormal due to a cyst or tumour.
Another way of assessing the testicles is to use ultrasound.