A sperm cell delivers its DNA to and fertilizes eggs, according to the National Center for Biotechnology Information. The BBC points out that this genetic material is contained in 23 chromosomes, which combine with the 23 chromosomes found in the female sex cell to make 23 pairs of chromosomes that contain all the genes for the new embryo.
The National Center for Biotechnology explains that sperm cells have two parts: the head and the tail. The head contains tightly packed DNA, and the tail is a flagellum that propels the sperm to the egg.
How Stuff Works elaborates that these sperm cells are delivered through semen, which includes fluid from the male vesicles and the prostate gland in addition to the sperm. Along with providing an environment for the sperm to move in, semen also protects and nourishes them.
According to the Open University, men produce millions of sperm cells. A single ejaculation contains up to 1,800 million of these cells. Sperm is produced in the testes in little vessels called seminiferous tubules, and they mature in the vas deferens in a process that takes up to 74 days and requires a slightly cooler environment than body temperature. If not ejaculated, the sperm are merely reabsorbed into the body.