In Matthew 19:3-9, Jesus points the Pharisees back to Genesis, to God's original intention for humanity. Similarly, to understand who we are now, we must first go back to Eden. Only by discovering that original plan can we understand our own lives and find the answers to our questions about sex and marriage. 

Saint John Paul II used the first six years of his papacy to unveil what is now known as the “Theology of the Body.” This teaching is framed within God's unfolding plan for humanity- from the beginning of man to his authentic destiny.The only way we can possibly understand or imagine these reference points is through God's authoritative word in the Bible. 

The creation story is indeed mythical - not in the sense that it is fictional, but in that it uses symbolic language to reveal profound truths about God and about the human condition. The ancient authors of Genesis were master psychologists as well as brilliant theologians. While the narrative refers to a real event at the dawn of human history, it contains much more than a purely literal account could convey.
Only through what Scripture tells us about the beginning can we know what human life was meant to be, since our own experience is marked by sin and its consequences. The point of returning to the beginning is not only to rediscover the meaning of marriage but also to help us grasp the significance of being male and female. - Mary Healy, Men and Women are From Eden