The egg cell, or ovum, is the largest and most important cell in the world - and it's only found in women!

Although men produce over a million sperm an hour, women are born with a lifetime trove of several million eggs. By adulthood, only about 400,000 remain, and over the course of life, most of the rest - nearly 1,000 a month - are lost. In fact, only about 450 of the millions of egg cells will ever get even a chance to become a baby.

Every day of a woman's fertile life, several dozen eggs begin developing. Normally, only one will complete the development cycle every month - the rest perish. But the mature egg gets to leave the ovary and take a daring journey down a fallopian tube where it has the chance of encountering eligible sperm.

Like a princess in a fairytale, an egg cell has only about a single day to survive before finding a mate - though because sperm cells can survive for up to 5 days inside a woman's body, a woman can be fertile for nearly a week.

But egg cells are monogamous; after one sperm has gotten into its heart, the egg hardens its outer wall to ward off any additional suitors.

There are many obstacles - and fierce competition - to becoming the perfect couple. But if all goes well, and the sperm and egg manage to find each other, it can lead to a miracle and a match made in heaven.