Genesis 19:36 in the King James Version
Thus were both the daughters of Lot with child by their father.
Context
35 They made their father drink wine that night also. The younger went and lay with him. He didn’t know when she lay down, nor when she got up.
36 Thus both of Lot’s daughters were with child by their father.
37 The firstborn bore a son, and named him Moab. He is the father of the Moabites to this day.