Fertilization

Diagram of fertilization

After the semen has been released from the male reproductive organ into the female reproductive organ, the sperm cell swims to the egg cell to fuse with it in order to form a zygote. This process is what we refer to as fertilization

A single ejaculation during sex contains millions of sperms but only one of the sperms is needed to fuse with the egg cell in the female reproductive organ. The sperm swim towards the egg cell. Only one of the sperms gets through the membrane of the egg cell. The tail breaks off and the head of the sperm fuses with the nucleus of the egg cell. Fertilization normally occurs in the upper part of the Fallopian tube inside the body of the female.

Summary: The sperm swims to the egg and fuses with it. The egg is now fertilized and develops into a zygote.