Where Did Cain Get His Wife?

This is one of the most asked bible question. Adam was the first man (1 Cor. 15:45). Eve is the mother of all living (Gen. 3:20). Genesis 5:4 says that Adam and Eve had both sons and daughters besides Cain, Abel and Seth. So Cain married one of his sisters.

"Now wait a minute," someone might say, "doesn't the Bible forbid brothers and sisters to marry?" Yes it does, but that law came many, many years later (in Lev. 18-20). During the time of Cain it was ok to marry siblings. Here's why:

Our genes have mistakes in them. When people who aren't related have children the child inherits different bad genes. But if relatives have children there is a much greater chance that the child will inherit the same bad genes. The bad genes lead to birth defects.

But before the fall of man, Adam and Eve had no bad genes (Gen. 1:31). Cain and his brothers and sisters had bad genes, but not many. As time went on, the amount of bad genes humans carry increased to the point where God had to forbid relatives to marry and have children.