The Handmaid’s Tale is based on the story of Genesis, in which God creates man and woman in His image and assigns them the task of populating the earth. In the beginning, there was only Adam; he had no wife. Then God created Eve from one of Adam’s ribs.
The Bible tells us that God wanted to fill the earth with people who were like Him: good, kind, and loving. So He said “it is not good for man to be alone,” and told Adam to go find a woman for himself.
But there were two problems: first, there were no women yet; second, there was nothing for Adam to eat except fruit from trees on Earth. So God caused sleepiness to come over him and took one of his ribs (probably from his side) and made it into a woman named Eve!
And then they had children! Lots and lots of children—at least 8 boys and girls between them altogether before they died off (some say because they ate an apple).
But their children didn’t have any children yet either until Abraham came along—he was both old enough to be their grandfather AND their father since his own parents had already died.