Why is reproduction at the heart of all creation?
Reproduction is central because God designed all creation, including the human race, to continue through reproductive organs; He took that part from Adam and built the woman as his complement, making man and woman complete. Thus the reproductive process is not incidental but the very heart of creation.
Les explains that the reproductive process of not only the human race but of all God's creation is based on those reproductive organs, and that is the very heart of all creation. In the Genesis account, God removes that part from Adam and surrounds it with the body of the woman, so now there is man and woman. As yet she is not called Eve but merely the woman. Adam says she is bone of his bones and flesh of his flesh, and she shall be called woman because she was taken out of man. God brings this new creature to Adam as his helpmeet, a word meaning complement, that which makes complete. Adam was not complete until God brought him that helpmeet. Even the New Testament uses the same word regarding Christ and the Church: the Church is the complement, and the Lord Himself looks forward to the day when He will have the body of Christ with Him, and we become the completion of even Christ Himself. There is a correlation between Adam and Eve, or husband and wife, and husband and wife as seen in Ephesians.