Genesis 19:35-37

Amplified Bible

³⁵ So they gave their father wine that night also, and the younger got up and lay with him; and again he did not know when she lay down or when she got up. ³⁶ Thus both the daughters of Lot conceived by their father. ³⁷ The firstborn gave birth to a son, and named him Moab (from father); he is the father of the Moabites to this day.