No, the Bible does not indicate that the serpent had a sexual union with Eve, nor that the serpent fathered Cain. The idea that Satan physically impregnated Eve is part of a false teaching sometimes called the “serpent seed doctrine.” It is not found anywhere in Scripture, and it contradicts the plain biblical account.

The Bible clearly states what happened: serpent lied and deceived Eve into eating the forbidden fruit. There is no mention of sexual activity, no hidden symbolism and no suggestion that Cain’s father was anyone other than Adam.

The account of Adam and Eve and the serpent in the Garden of Eden is found in Genesis chapters 2 and 3.  “The LORD God took the man and put him in the Garden of Eden to work it and take care of it. And the LORD God commanded the man, “You are free to eat from any tree in the garden; 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” (Genesis 2:15-17).  After Adam had been in the Garden for a time, the Lord made a “suitable helper for him,” a woman made from Adam’s rib (Genesis 2:20-22).

Adam and Eve must have been very happy in the Garden of Eden, a paradise where all their needs were taken care of and where they had perfect communion with God. But “the serpent was more crafty than any of the wild animals the LORD God had made. He said to the woman, ‘Did God really say, You must not eat from any tree in the garden?’ ” After Eve responded that God had told them they must not eat of the one tree or even touch it, or else they would die, the serpent told his first great lie, “You will not surely die” (Genesis 3:2-4).

Eve was deceived (or tricked – see 2 Corinthians 11:3); she ate the fruit, and gave some to Adam, who also ate it.  Now they had to pay the consequences.  In verses 17 to 19 of chapter 3, God told Adam he would now have a hard life, and in the end he would die.  

Nothing in the text hints at sexual behavior. The fruit was actual fruit, not a metaphor for intimacy. The consequences God pronounced — pain, toil, death — all relate to disobedience, not immorality.

But who was this serpent who could talk? In Revelation 20:2, pertaining to the last days, we read, “[An angel] seized the dragon, that ancient serpent, who is the devil, or Satan, and bound him for a thousand years.” (Italics added) In John 8:44, our Lord Jesus accused the Jewish people who were questioning him, “You belong to your father, the devil…When he lies, he speaks his native language, for he is a liar and the father of lies.” Satan, the “father of lies,” spoke through the serpent in the Garden, in order to deceive Eve and to cause Adam to sin.

But God also pronounced judgment upon the serpent.  One of the things God told the serpent was, “I will put enmity between you and the woman, and between your offspring and hers; he will crush your head, and you will strike his heel.”  (Genesis 3:15) This was the first hint that God would eventually send a Savior, and the serpent would be destroyed.

Some people misunderstand this verse and claim it means Eve had physical offspring with the serpent, but the Bible plainly states Cain’s father was Adam. Genesis 4:1 says, “Adam knew Eve his wife, and she conceived and bore Cain.” There is no alternate version, no hidden meaning, and no second father mentioned. Cain was fully human, born in the normal way, and inherited Adam’s fallen nature just like every other human being.

Adam’s sin brought imperfection and death into the human family, and all of Adam’s descendants inherited that fallen condition. But God provided a solution: He sent His perfect son, Jesus Christ, to die as a ransom for Adam and his race. “For since death came through a man, the resurrection of the dead comes also through a man. For as in Adam all die, so in Christ all will be made alive” (1 Corinthians 15:21 22). In God’s due time, all will return from the grave and have the opportunity to learn righteousness.

As for Cain, he was Adam and Eve’s first child (Genesis 4:1). He became the first murderer, but he will rise from the dead; and if, after a period of judgment, he accepts God’s righteous way, he will also gain perfect human life. “Do not marvel at this; for an hour is coming, in which all who are in the tombs will hear His voice and will come forth; those who did the good deeds to a resurrection of life, those who committed the evil deeds to a resurrection of judgment” (John 5:28, 29 NASB).

Additional Resources:
Christian Questions Podcast
Episode #1305: “How Do Satanic Demons Influence Our World?”
Establishing the origin, power and methods of dark spiritual beings
Preview Video
CQ Rewind Show Notes

For children, parents and Bible class teachers:
Animated video: Who is Satan?
Animated video: Why didn’t God stop Satan from tempting Eve?