Sperm are very small male sex cells. They are created in the testicles, in the process of spermatogenesis, which lasts 74 days. From the testicles, they go to the epididymis, through which they pass for 11- 12 days and mature along the way. The entry of sperm into the back of the urethra is called emission, and the expulsion from the urethra is called ejaculation. There are about 50 million sperm per milliliter in a man’s ejaculate, and the limit of the normal sperm count according to the World Health Organization is 20 million per milliliter. Sperm ejected from the penis into the female genital organ move towards the fallopian tube using the tail. There they fuse with the egg and thus fertilize it. There are 23 chromosomes in each sperm.