After a man turns 12, his penis will grow rapidly.

Boys enter puberty after the age of 12, and their testicles increase rapidly. The testicle volume of adult males is 16-25 ml, with an average of 19.8 ml.

The size of the testicles has a certain relationship with age.

From newborn babies to children under 12 years old, the testicles are in a relatively dormant period with a volume of about 1-4 ml. Boys enter puberty after the age of 12, and their testicles increase rapidly. The testicle volume of adult males is 16-25 ml, with an average of 19.8 ml. After the age of 60, men enter the stage of sexual decline, and the testicular volume gradually decreases. After the age of 70, the testicular volume can shrink to less than 16 ml.

Testicle size: If the testicle volume of an adult is less than 10ml, it is considered microtestis, which may lead to sexual dysfunction and male infertility. If the testicles are too small, the spermatogenesis function of the testicles may be impaired, resulting in a small number of sperm or even no sperm, and most of them will lose their fertility function. Examination shows very low plasma testosterone levels, underdeveloped male secondary sexual characteristics, sparse beard, pubic hair and axillary hair, low and thin voice, and feminine behavior in severe cases. Most patients have low libido and sexual dysfunction.

The diseases that cause microorchia mainly include Klinefelter's syndrome, congenital adrenal hyperplasia and some hereditary diseases.

Testicular abnormalities are mostly caused by diseases such as testicular tumors, epididymal tuberculosis, and testicular hydrocele. If these diseases are not treated in time, they will affect fertility or cause poor quality of sperm and semen, thus leading to infertility.