The union of sperm and the egg is fertilization.

What is ovulation?

An egg is released every month from the girl’s ovaries and normally it will take few days (4 days) to travel down the fallopian tube. This egg can make her pregnant. It is a joint work between brain and ovary with the help of the hormones. If a sperm do not meet with the egg during this time, then there is no possibility to become pregnant.

What will happen if the sperm do not meet the egg?

If there is no foetus to nourish, the lining of the uterus comes out with blood approximately after 14 days and this is the period.

What is the process of fertilization?

Fertilization starts with sexual intercourse and the ejaculate contains millions of sperms. They swim upwards and may meet an egg in the fallopian tube. Only a single cell may penetrate the egg’s membrane. The egg is covered by two protecting layers so that normally fertilization by more than one sperm is not possible. But there are exceptions.