There is no testicle replacement period for boys. A man has only one pair of testicles in his lifetime. The main function of testicles is to produce sperms and male hormones, which can maintain the development, libido, and reproductive aspects of men. Normally, testicles are not replaced; if you have a testicular tumor or other related condition, the diseased part will be removed. If nothing else, testicles do not replace themselves. The male testicle is one of the vital organs of the male body. The testicular parenchyma consists of the varicocele and connective tissue, among other things. Sperm are produced in the epithelium of the seminiferous tubules, and the interstitium can synthesize and secrete androgens. The testes are also regulated by the hypothalamus and pituitary gland. There is also complex autocrine or paracrine regulation within the testes. Testicles do not replace themselves and prompt medical attention is recommended in case of discomfort.