In the first creation account of man and woman, they are told to
be fruitful and multiply. They are not given laws.

Genesis 1: 26Then God said, “Let Us make man in Our image, according to Our likeness; and let them rule over the fish of the sea and over the birds of the sky and over the cattle and over all the earth, and over every creeping thing that creeps on the earth.” 27God created man in His own image, in the image of God He created him; male and female He created them. 28God blessed them; and God said to them, “Be fruitful and multiply, and fill the earth, and subdue it; and rule over the fish of the sea and over the birds of the sky and over every living thing that moves on the earth.” 29Then God said, “Behold, I have given you every plant yielding seed that is on the surface of all the earth, and every tree which has fruit yielding seed; it shall be food for you; 30and to every beast of the earth and to every bird of the sky and to every thing that moves on the earth which has life, I have given every green plant for food”; and it was so. 31God saw all that He had made, and behold, it was very good. And there was evening and there was morning, the sixth day.

However, the garden of Eden and Adam and Eve are different. They are the bloodline that Christ would come through. Whether you believe in a 8 day creation or just that Adam and Eve were created separately on the 6th day, it is clear they are separate in the whole world from the other men and women create by God.

Genesis 2: 7Then the LORD God formed man of dust from the ground, and breathed into his nostrils the breath of life; and man became a living being. 8The LORD God planted a garden toward the east, in Eden; and there He placed the man whom He had formed. 9Out of the ground the LORD God caused to grow every tree that is pleasing to the sight and good for food; the tree of life also in the midst of the garden, and the tree of the knowledge of good and evil.

Garden of Eden

Satan tries to destroy this bloodline when the time is right…

Genesis 2:  18Then the LORD God said, “It is not good for the man to be alone; I will make him a helper suitable for him.” 19Out of the ground the LORD God formed every beast of the field and every bird of the sky, and brought them to the man to see what he would call them; and whatever the man called a living creature, that was its name. 20The man gave names to all the cattle, and to the birds of the sky, and to every beast of the field, but for Adam there was not found a helper suitable for him. 21So the LORD God caused a deep sleep to fall upon the man, and he slept; then He took one of his ribs and closed up the flesh at that place. 22The LORD God fashioned into a woman the rib which He had taken from the man, and brought her to the man.

Satan throughout time has tried to destroy Gods plan. He is in rebellion against God.

Genesis 3: 1Now the serpent was more crafty than any beast of the field which the LORD God had made. And he said to the woman, “Indeed, has God said, ‘You shall not eat from any tree of the garden’?” 2The woman said to the serpent, “From the fruit of the trees of the garden we may eat; 3but from the fruit of the tree which is in the middle of the garden, God has said, ‘You shall not eat from it or touch it, or you will die.’” 4The serpent said to the woman, “You surely will not die! 5“For God knows that in the day you eat from it your eyes will be opened, and you will be like God, knowing good and evil.”

God created a cherub named Lucifer — PERFECT IN HIS WAYS, but with the POWER OF FREE CHOICE — and LUCIFER TRANSFORMED HIMSELF INTO A DEVIL by his rebellion against God! By his rebellion, Lucifer BECAME Satan. By his OWN CHOICE in OPPOSING God, he made himself God’s adversary.

Before Satan fell from grace, he was a good, enlightened angel. In fact, he was anointed as a guardian cherub, and he was blameless from the day he was created, until wickedness was found in him (Ezekiel 28:14,15). Then he, and his throne were cast down to the earth. (Isaiah 14:12,13).

http://howlongolord.com/the-katabol-satans-war-with-god/

The “knowledge” that the serpent promised to Adam and Eve was also sexual or reproductive in nature, and was a plan to defile the bloodline that Christ would come through. Adam and Eve had gained the knowledge of reproduction and of new life, and through their “transgression”, death entered into the world.

Cast out of Eden

The deuterocanonical text, Baruch claims that the Serpent had sexual or reproductive relations of some sort with both Adam and Eve:

For going to Eve he deceived her and committed adultery with her, which is contrary to the law; and he went also to Adam and used him as a boy, which is also against the law. Hence arose adultery and pederasty.

The Gospel of Philip suggests something rather similar:

First adultery came into being, afterward murder. And he was begotten in adultery, for he [Cain] was the child of the serpent.

Jesus refers to this same idea later in the book of of John:

John 8: 44“You are of your father the devil, and you want to do the desires of your father. He was a murderer from the beginning, and does not stand in the truth because there is no truth in him. Whenever he speaks a lie, he speaks from his own nature, for he is a liar and the father of lies.

Cain, the first murderer leaves Adam and Even and goes to a foreign land and finds a wife after killing his brother:

Genesis 4: 15So the LORD said to him, “Therefore whoever kills Cain, vengeance will be taken on him sevenfold.” And the LORD appointed a sign for Cain, so that no one finding him would slay him. 16Then Cain went out from the presence of the LORD, and settled in the land of Nod, east of Eden. 17Cain had relations with his wife and she conceived, and gave birth to Enoch; and he built a city, and called the name of the city Enoch

The bloodline of Cain is separate from Adam and Eve. Adam and Eve will later have a grandson called Enoch through their son Seth:

Cain

The eldest son of Cain ( Genesis 4:17 ), who built a city east of Eden in the land of Nod, and called it “after the name of his son Enoch.” This is the first “city” mentioned in Scripture.

Adam and Eve

The son of Jared, and father of Methuselah ( Genesis 5:21 ; Luke 3:37 ). His
father was one hundred and sixty-two years old when he was born. After the
birth of Methuselah, Enoch “walked with God three hundred years” ( Genesis 5:22-24 ), when he was translated without tasting death. His whole life on earth was three hundred and sixty-five years. He was the “seventh from Adam” ( Jude 1:14 ), as distinguished from the son of Cain, the third from Adam. He is spoken of in the catalogue of Old Testament worthies in the Epistle to the ( Hebrews 11:5 ). When he was translated, only Adam, so far as recorded, had as yet died a natural death, and Noah was not yet born. Mention is made of Enoch’s prophesying only in Jude 1:14 .

 The Book of Enoch was never included in the Bible we have today. However, it is referenced many time throughout the other books as listed above. It is a retelling of the Genesis story and the fallen angels that come to earth to manipulate the bloodline and the Genetics of man by angels mixing with human woman. We see this also in Genesis:

Genesis 6:  1Now it came about, when men began to multiply on the face of the land, and daughters were born to them, 2that the sons of God saw that the daughters of men were beautiful; and they took wives for themselves, whomever they chose. 3Then the LORD said, “My Spirit shall not strive with man forever, because he also is flesh; nevertheless his days shall be one hundred and twenty years.” 4The Nephilim were on the earth in those days, and also afterward, when the sons of God came in to the daughters of men, and they bore children to them. Those were the mighty men who were of old, men of renown.

The Nephilim are fallen angels. They are referenced in the book of Jude also:

Jude 1: 6And the angels who did not stay within their own position of authority, but left their proper dwelling, he has kept in eternal chains under gloomy darkness until the judgment of the great day

The Nephilim account here is from the the Book of Enoch – The Watchers:   

https://en.wikipedia.org/wiki/Book_of_Enoch

 If you read the account in the text of Enoch, you find the fallen angels are locked away in chains in darkness. Mention of angels who physically descended (and figuratively “fell”) to Mount Hermon is found in the Book of Enoch, which the Ethiopian Orthodox Church and Eritrean Orthodox Tewahedo Church accept as biblical canon  .