A sperm is a the male reproductive cell or gamete containing the half set of chromosomes that create a zygote when combined with a female gamete. The zygote is the beginning of what will eventually become a child. Sperm is produced in the male reproductive organs and is carried in semen. When ejaculated out of the penis, only about five percent of semen contains 50 million sperms.
During male fetal development, germ cells settle in the gonads and wait for puberty. At puberty, the germ cells begin to divide to produce sperm. As from puberty until death, a man produces billions of sperms. It takes about a week for each sperm cycle from production until it is ready for release. Other semen contents are produced by the glands. This includes clotting compounds to keep semen together in the female reproductive tract and sugars to feed the sperm on the journey towards the egg. In the process of making a child, a few hundred sperm make it into the female reproductive tract where they begin their highly competitive journey to reach and fertilize the egg.
The sperm has a head full of enzymes which are crucial for penetrating the wall of the egg. In size, the sperm is very tiny compared to the egg and the strong enzymes allow it to be able to effectively penetrate the wall. The sperm also has a tail, the flagella, which allows it to swim up the female reproductive tract. As soon as the sperm successfully penetrates the egg wall, the tail will drop off.