The testes are internal male reproductive organs. A normal male has two testicles, located on the left and right side of the scrotum. The testicles are oval in shape and gray in color. In adults, the testicles are 3.5-4.5 cm long, 2-3 cm wide and 1-2 cm thick, and each side weighs 10-15 grams. The left side is usually about 1 cm lower than the right side. Some people have a large and small testicle, one high and one low, if the difference is not big, are normal. Testicular examination The testicles have two main functions, sexual function and reproductive function, androgen and sperm mainly come from the testicles, testicular examination is mainly to evaluate the male sexual function and reproductive function. Testicular examination mainly includes testicular biopsy, testicular self-examination and transillumination test. 2, testicular self-examination Whether the testicles are normal or not, in addition to going to the hospital for examination, you can also self-examine in general. 3.Semen volume The volume of semen excreted by normal people at one time may vary according to the abstinence time, generally 2-5ml, less than 1.5ml or more than 8ml is considered abnormal. 4.Male calculator body scan (CT) Male calculator body scan (CT) can diagnose prostate gland, seminal vesicle gland, testicular development abnormalities, testicular tumor, testicular sphincter effusion. 5. External genital examination The examination of external genitalia can be performed by specialists, mainly including male external genitalia and female external genitalia. People can also self-examine to help early detection of certain diseases.