Who Fathered Cain?

There's quite a few people that believe that satan fathered Cain, which would supposedly explain why Cain killed his brother Abel. According to the story the Cain bloodline then went on from bad to worse, and was then killed off by the Flood.

That's of course not what the Bible says. Adam was the father of Cain. Plain and simple.

And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the LORD. And she again bare his brother Abel. And Abel was a keeper of sheep, but Cain was a tiller of the ground.
- Genesis 4:1-2 (KJV)

And no, Cain and Abel weren't twins either (another common misconception), otherwise the Bible would have said so. In fact, it uses the word twins later in Genesis, so yes, there is definitely a Hebrew word for twins.

When I started doing a more detailed Bible study on this, I ran into a pre-existing Bible study.

It does a pretty good job on debunking the whole "satanic bloodline" issue, so you might as well read that, if you want to learn more.

Just remember that the wickedness of man was great in those days, not because of "satanic bloodlines", but because of each person's own thoughts.

And God saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually.
- Genesis 6:5 (KJV)

God will hold us all individually accountable.

So then every one of us shall give account of himself to God.
- Romans 14:12 (KJV)