Self-examination of both testes is important for early detection of testicular cancer (TC). The most common method of early detection is performing a monthly exam. Since TC is usually isolated to a single testicle, comparison of each testicle can be helpful. It is normal for one testicle to be slightly larger than the other. Your focus should be noticing any lumps, bumps, or changes from the previous month
Upon reaching puberty, all men should conduct a monthly testicular self-exam and ask your doctor during your yearly physical to perform one as well.