IN MY OPINION: we must first establish and apply what we know about Adam & Eve and early creation. Which; although we know very little, there is no easy explanation and the debate could be lengthy. Therefore in my personal study I have formed an opinion of what the 'Garden' really was-and still is; and the nature of "humans" in the Garden before they were 'evicted' so to speak.Hmm very interesting! So how could it have been, not as we know it?
The pain of childbirth was a curse that followed Eve's sin. They could have unprotected sex before. They also did not age much / fast until they sinned. I also think it didn't take long for Eve to get tempted. She was temtped when she first stood in front of the tree and wondered about its fruit. Assuming this happend after 100 years is madness, after 1 day makes more sense.So why did Adam and Eve only have babies after they sinned? Why didn't they have babies before, in the Garden of Eden?
I don't think there is any real answer, but thoughts are welcome. Just a fun thought!