I watch the TV show The Last Man on Earth and there is only a handful of women and men living. In the show the few are trying to conceive. They haven't covered how eventually they will have to inbreed a generation or 2 away.
In the event that mankind is wiped out to a handful of people and not enough for genetic diversity could the amount of people needed to repopulate the Earth be reduced by using Gene Editing and Modification?
Although several people survives in remote parts of the world only a few had good DNA, age and disease free to procreate.
With the help of a geneticists and a salvaged lab could DNA be modified to have your siblings baby but healthy?
As science progresses the plausibility of Adam and Eve giving rise to a whole world sounds more and more realistic to me. Can humans be so genetically perfect not to have defect for many generations?