What is Fertilization

Following copulation, a male will release millions of sperm cells from his erect penis into a woman's vagina.

The sperm travels through the vagina into the cervix.

They travel through the uterus into the fallopian tube. They are attracted by chemicals called ‘chemotaxis’ released by the egg.

There are numerous barriers throughout the journey. The pH of the female's reproductive system will kill some sperm cells, others will get caught in tiny thread like structures called cilia in the uterus, others will not be able to get through the cervix.

The sperm can survive in the uterus for five days.

An egg is released from the ovary on the day of ovulation midways through a woman's cycle.

The egg will only survive 2 days.

The cilia push the egg along the fallopian tube.

Only a few hundred reach the egg out of millions.

Sperm surround the egg. One sperm is able to penetrate the egg, and fuses to form a Zygote. No more sperm can fertilize the egg.