Sperm Facts

Sperm are as crucial to conception as a woman's eggs and her ability to carry a child to term. There can be up to 600 million sperm in a single ejaculation containing an average amount of semen. Each sperm takes approximately 10 weeks or 70 days to reach maturity and the average man produces from 70 to 150 million sperm daily. A mature sperm can remain in the body for up to two weeks before being released. The male body stores them in the epididymis, a coil-like structure located across the top of each testicle. If the sperm aren't ejaculated, they're simply absorbed again into the body.

Parts of a Sperm

Sperm are tiny and are made out of three parts that can only be seen under a microscope. These three parts are the head, midpiece and tail. The head has special enzymes to help it penetrate the thick wall of a female egg. As many as 200 million sperm can reach the egg and most bounce off the surface. When one penetrates the surface fertilization occurs.

The midpiece of a sperm can be considered the muscle part of the sperm. It has a core that produces a chemical energy that gives the sperm the power for the long journey through a woman's cervix, uterus and finally into the fallopian tubes. The tail lashes back and forth to propel the sperm. It's the longest part of the sperm. If the sperm is strong enough to reach the egg in a fallopian tube, conception occurs.

Men who have fertility issues where their sperm isn't strong enough to make the journey can still get their partners pregnant through assisted reproductive technologies. Some forms of assisted reproductive technology collect sperm and manually inject the sperm into an egg in a sterile laboratory setting.

The Sperm's Role in Fertilization

The creation of a new human being is a complicated process involving the precise and perfect balance of hormones by both partners. A lot of information is available about what happens to the egg as it's created and after it's fertilized. Not as much information is available about the sperms role.

The first sperm that reaches the egg releases a special enzyme to eat through the outer layer (zona pellucid) of the egg. The two fuse together and the sperm releases hormones that start a series of chemical reactions that metabolically activate the egg. A process of DNA replication begins. Sometimes a single sperm divides a single egg into two separate eggs. If this happens, identical twins are conceived. Fraternal twins are conceived when two eggs are fertilized.