In short, this is all about what actually happened in the Garden of Eden.

Many of us were taught from childhood that Eve ate an apple which she took from the tree of the knowledge of good and evil.

It is amazing how many people not only accept this but become outraged when they hear what I believe is a more correct version of this event.

This assumes that the reader is a Christian and believes in the Bible.

I am going to post Bible verses here with just a few words of my own to explain what is going on. I will also be including definations from the Hebrew dictionary of a standard Strong's Concordance.

First I would like to demonstrate that Satan does exist and the sons of God were actual angels. For this we will go to the book of Job:

Job 1:6
6 Now there was a day when the sons of God came to present themselves before the LORD, and Satan came also among them.
KJV

Job 2:1
2:1 Again there was a day when the sons of God came to present themselves before the LORD, and Satan came also among them to present himself before the LORD.
KJV

The reason for these verses is the fact that all too many people try to say that the "sons of God" were human princes or some sort of mighty men. These verses show that Satan along with the sons of God presented themselves before the LORD, a thing which human beings can not do.

Genesis 6:2
2 That the sons of God saw the daughters of men that they were fair; and they took them wives of all which they chose.
KJV

Why does one take a wife?

Genesis 6:4
4 There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown.
KJV

Now we know that the sons of God were angels, took wives of the daughters of men (Adam) and the women bare children unto them.

Now we have enough background to go to the Garden of Eden.

While Eve was talking to the Serpent, something happened, just after the Serpent lied to Eve:

Genesis 3:3-4
3 But of the fruit of the tree which is in the midst of the garden, God hath said, Ye shall not eat of it, neither shall ye touch it, lest ye die.

4 And the serpent said unto the woman, Ye shall not surely die:
KJV

Who is this serpent? Is it a snake as many believe? Let's get the serpent identified right now:

Revelation 12:9
9 And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
KJV

Wow, that old serpent is identified as being the same as the dragon, the Devil and Satan! So this is who was talking to Eve, it was the serpent who was more subtil than any beast of the field.

OK, Let's skip until just after the deed done in the Garden and see what God has to say to Adam and Eve after the fact:

Genesis 3:14-15
14 And the LORD God said unto the serpent, Because thou hast done this, thou art cursed above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life:

15 And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.
KJV

Here it is, straight from the mouth of God. God is going to put emnity between the serpent and the woman and the serpent's seed and the woman's seed.

I did not make this up, I just reworded Genesis 3:15 a bit, I did not change it's meaning. One thing that I need to point out in the Genesis 3:14-15 verses above, the deed is done! There is a "thy seed" at this point. The "her seed" is about to take place.

Genesis 4:1-2
4:1 And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the LORD.

2 And she again bare his brother Abel. And Abel was a keeper of sheep, but Cain was a tiller of the ground.
KJV

The book of Genesis covers thousands of years, I believe that very little time time took place between Genesis 3:14-15 and Genesis 4:1-2, here is why.

again: OT:3254
yacaph (yaw-saf'); a primitive root; to add or augment (often adverbial, to continue to do a thing):
KJV - add, again, any more, cease, come more, conceive again, continue, exceed, further, gather together, get more, give more-over, henceforth, increase (more and more), join, longer (bring, do, make, much, put), (the, much, yet) more (and more), proceed (further), prolong, put, be [stronger-], yet, yield.

I am accepting the defination "to continue to do a thing" and here is why:

Genesis 4:3-4
3 And in process of time it came to pass, that Cain brought of the fruit of the ground an offering unto the LORD.

4 And Abel, he also brought of the firstlings of his flock and of the fat thereof. And the LORD had respect unto Abel and to his offering:
KJV

According to Genesis 4:3-4 both Cain and Abel came of age at the same time, both giving a sacrafice on the same day.

It is important to keep in mind, from the beginning of this post, if the sons of God could conceive children, there is no reason that Satan could not also conceive a child.