Just like the days of Noah and Lot were, so will be the days before the coming of the Lord, page-126

The Gene pool after the flood wouldn't have been good. Noah's grandchildren would have been marrying Cousins at best maybe even brothers & sisters. Evidently inbreeding was ok back then
Those who insist that Noah's Flood was a literal event conveniently forget that, along with numerous other issues which render a literal Noah's Flood to be impossible.