RE: Cain made love to his wife, and she became pregnant and gave birth to Enoch.
Sure, but I guess he had to make love to his sister or his niece.
“aha, the Garden of Eden was in West Virginia” punchline coming in 3....2....1.....
He did, but at that time, God had not declared that to be sin. God allowed it in the early stages of humanity with Adam's early descendents.