A man died and went to Heaven. There were thousands of other people there. They were all naked and all looked as they did at the age of 21. He looked around to see if there was anyone he recognised. He saw a couple and he knew immediately that they were Adam and Eve.
How did he know?
Before the flood people live 500 years or more having who knows how many children per couple. If heaven only had thousands and not millions or billions then he may have known them on earth.
Also, if you think about it. You have 2 parents, 4 grandparents, 8 great grandparents... ect. So if you keep going you exceed the population of the planet well after the death of Christ. Therefore we are all products of some sort of distant incest without reguard to creation vs evolution.
Another solution
