What are sperm?
Sperm are the male reproductive cells. In order to produce a child, the genetic material from the sperm must combine with the genetic material from an egg, in a process called fertilisation. Healthy, fully developed sperm are very small (0.05 millimetres long) and cannot be seen by the human eye. These mature sperm are highly specialised cells and are made up of three parts: a head, neck and tail. In the head is a structure called the nucleus, which contains 23 tightly packed chromosomes (genetic material). The head is designed to stick to and then enter (penetrate) the egg. The neck joins the head to the tail. The part of the tail nearest the neck contains the mitochondria, which provides the energy for the sperm to move. The tail moves in a whipping motion to push the sperm towards the egg. A man’s fertility and sexual characteristics depend on the normal functioning of the male reproductive system.
