In the normal male cycle, it takes 10-12 weeks for sperm to be produced and for sperm to mature. Sperm first form primary spermatogonia in the testes and then mature gradually, a process that generally takes 8-10 weeks. These primary spermatozoa then pass through the vas deferens to the epididymis for maturation, which takes about 2 weeks. The mature spermatozoa in the epididymis then pass through the vas deferens to the seminal vesicles for storage. If the spermatozoa need to be utilized, the seminal vesicles will contract and expel the mature spermatozoa from the body so that fertilization can take place and a fertilized egg can be formed, thus achieving the process of reproducing offspring. After a sperm is expelled, the testes sense the signal and produce new sperm again, a process that also takes 10-12 weeks. However, this time is not absolute, but is generally within this time frame, and can be shortened to about 70 days when sperm are expelled more frequently.