Men ejaculate 2-5 milliliters of semen per ejaculation, each milliliter of semen contains 20 to 200 million spermatozoa. Even without ejaculation, sperms will naturally wither and be engulfed in the epididymis. So a man’s lifetime sperm cannot be determined. Male sperm is mainly produced by the testes. Generally speaking, each time a man ejaculates 2-5 milliliters of semen, each milliliter of semen contains 20 to 200 million spermatozoa. The exact value cannot be accurately calculated and there is no clinically accurate value due to differences in male body condition, nutritional intake, and so on. It is worth noting that sperm production and discharge are affected by many factors, such as abnormal testicular development, testicular torsion, testicular trauma, testicular inflammation, testicular tumors, and so on. In addition, even without ejaculation, sperm will naturally wither and be engulfed in the epididymis. To summarize, so a man’s lifetime sperm cannot be determined.