What does Genesis 11:29 mean?
Several complicated family relationships are described in this verse. First, Abram married Sarai—who would later be renamed Sarah. We know from Genesis 20:12 that Sarai was Abram's half-sister, the daughter of his father Terah, but not from the same mother. Abram's brother, Haran, had died leaving behind at least three children: Milcah and Iscah, as well as Lot (Genesis 11:27). Abram's other brother Nahor married Haran's daughter Milcah.Later, God's Law for Israel would forbid marriages of family members so closely related. At this time, it seems, this was apparently a common practice and not forbidden by God. Most scholars see the potential for genetic problems in the children of close relatives as the reason God prohibits incest. This, most likely, would become a more and more serious issue as mankind continued to live in a fallen, corrupted, post-flood world.