Genesis 4:17 mentions Cain’s wife. Where did she come from? Were there humans other than those who came from Adam and Eve?

All the families of the earth originated with Adam and Eve. Therefore, Cain’s wife was either a sister, niece, or great niece. While laws against marriages between close relatives would later be put in place, such marriages were necessary in the early years of man’s existence.

Some read the Genesis account and are left with the impression that Cain, Abel, and Seth were the only children Adam and Eve had, but Genesis 5:4 says plainly that Adam “had sons and daughters.” No doubt, Cain’s wife was one of Adam’s daughters or granddaughters.