I'm an atheist trying to accept the word of Christ, PLEASE help?

Adam and Eve were the first people(according to the Bible), and had more than three children. Cain, Able and Seth were supposed to be Adam and Eve's first three children, and because Adam lived to be 930, they probably had a good dose more, although it never tells you exactly how many more. What would have happened is that The brothers would have had children with their sisters, because at this point there was no commandment about , and was not believed to be wrong at that time. I'm agnostic, but I was raised in the church and believe that everyone should be able to believe what they want. If you need any more answers about scripture, I could try and help you.