My teacher early in grade school in a Catholic school. One of the students asked a similar question. The teacher said that because there were so few people, God allowed brothers and sisters to get married. That seemed to satisfy the class, and we moved on to something else.

But I have thought about it more deeply since then. We have the full story about Adam’s and Eve’s creation, and their first two children. But then after Cain kills Abel and God confronts him, he is afraid that people will harm him for his sin. And he eventually founded a city. Who were the people he was afraid of? Where did the inhabitants of the city come from?

What seems to me to be the most straightforward explanation: The fact that Adam and Eve were the first people created doesn’t mean that they were necessarily the only people created. God populated the world as he saw fit.

These are answers that fit within the confines of the story of Adam and Eve in Genesis. But the larger issue is that Adam and Eve did not really exist. They are mythical characters, and they are part of a story told to impart lessons about the relationship between people and God. There is no need to think that their story is a factual, historical, account.

Christians seem to have a great deal of angst about this one. There is a strand that says Adam and Eve must have had other contemporary children not mentioned in the Bible, implying that Cain married his sister (ignoring the sensible advice to try everything in life except incest and clog dancing). (For completeness, later, in Genesis 5, Adam did go on to have another son, Seth, when he was 130 years old plus various other unnamed sons and daughters, finally dying when he was 930 years old. What Eve felt about all this geriatric begetting is not recorded).

Genesis 4 v16 has Cain going to the land of Nod, where he marries, builds a city and has children. As usual, the woman he marries doesn’t count in the male-dominated Bible and doesn’t get named. So there are just two possible options:

Adam and Eve were the first humans One of their children, one of Cain’s sisters, had already left Eden and set up in Nod and there Cain married her

OR

There was at least one other contemporary human settlement, Nod, in existence alongside Eden, so Adam and Eve weren’t the only humans around.

Look, the whole story was written a long long time ago. As a story it has enriched our culture irrespective of its very obvious factual flaws. But it tells us nothing at all about the existence or otherwise of divine beings.