The "beginning" being referred to is the beginning of the institution of marriage, when man and women were created, not the beginning of life itself.
OH???
Matthew 19
3. Some Pharisees came to him to test him. They asked, "Is it lawful for a man to divorce his wife for any and every reason?"
4. "Haven't you read," he replied, "that at the beginning the Creator `made them male and female,'
5. and said, `For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh' ?
6. So they are no longer two, but one. Therefore what God has joined together, let man not separate."
7. "Why then," they asked, "did Moses command that a man give his wife a certificate of divorce and send her away?"
8. Jesus replied, "Moses permitted you to divorce your wives because your hearts were hard. But it was not this way from the beginning.
Genesis 2
7. the LORD God formed the man from the dust of the ground (Not from pre-humans) and breathed into his nostrils the breath of life, and the man became a living being.
8. Now the LORD God had planted a garden in the east, in Eden; and there he put the man he had formed.
9. And the LORD God made all kinds of trees grow out of the ground--trees that were pleasing to the eye and good for food. In the middle of the garden were the tree of life and the tree of the knowledge of good and evil.
10. A river watering the garden flowed from Eden; from there it was separated into four headwaters.
11. The name of the first is the Pishon; it winds through the entire land of Havilah, where there is gold.
12. (The gold of that land is good; aromatic resin and onyx are also there.)
13. The name of the second river is the Gihon; it winds through the entire land of Cush.
14. The name of the third river is the Tigris; it runs along the east side of Asshur. And the fourth river is the Euphrates.
15. The LORD God took the man and put him in the Garden of Eden to work it and take care of it.
16. And the LORD God commanded the man, "You are free to eat from any tree in the garden;
17. but you must not eat from the tree of the knowledge of good and evil, for when you eat of it you will surely die."
18. The LORD God said, "It is not good for the man to be alone. I will make a helper suitable for him."
19. Now the LORD God had formed out of the ground all the beasts of the field and all the birds of the air. He brought them to the man to see what he would name them; and whatever the man called each living creature, that was its name.
20. So the man gave names to all the livestock, the birds of the air and all the beasts of the field. But for Adam no suitable helper was found.
21. So the LORD God caused the man to fall into a deep sleep; and while he was sleeping, he took one of the man's ribs and closed up the place with flesh.
22. Then the LORD God made a woman from the rib he had taken out of the man, and he brought her to the man.
23. The man said, "This is now bone of my bones and flesh of my flesh; she shall be called `woman, ' for she was taken out of man."
24. For this reason a man will leave his father and mother and be united to his wife, and they will become one flesh.
25. The man and his wife were both naked, and they felt no shame.