Where did Cain’s wife come from? What was her origin, is a good question that atheist’s come up with from time to time and deserves a real answer?
I will pose an answer to this question.
Adam lived several hundred years and likely had many children as God ordered them to be fruitful and multiply.
Genesis 1: 22
22 God blessed them, saying, “Be fruitful and multiply, and fill the waters in the seas, and let birds multiply on the earth.”
The Bible, however, does not give a chronology nor ages of these births. Since it is extremely likely that he had many children and hence, many women must have been present. He could have married a niece, sister, etc. and had many more children. Inbreeding would not have been a real issue as the genetic line would have been very pure. God’s law against incest did not come until much later in time:
Lev 18: 6-9
6 ‘None of you shall approach any blood relative of his to uncover nakedness; I am theLord. 7 You shall not uncover the nakedness of your father, that is, the nakedness of your mother. She is your mother; you are not to uncover her nakedness. 8 You shall not uncover the nakedness of your father’s wife; it is your father’s nakedness. 9 The nakedness of your sister, either your father’s daughter or your mother’s daughter, whether born at home or born outside, their nakedness you shall not uncover.