There is literally no reason not to fuck your relatives. Even the risks associated with inbreeding is no worse than a woman in her late 30’s.

A child with you and your healthy sister or daughter is not likely to result in any birth issues as long as you’re family doesn’t have genetic defects in their history.

It doesn’t cause mutants, it doesn’t cause retards at various times and cultures incest has and what constitutes incest changes drastically.

In the pre -Roman Middle East invest was a sacred act, in Rome it was only incest if it was somebody on our fathers side. Aunts and cousins on our moms side was fair game.

In some Amazonian tribes incest is common as group orgies are a regular occurrence among family groups.

Even in the western world cousin marriage was a common affair until about 100 years ago.

So if you have hot family you should try to fuck them, there is no reason not too, in fact you are foolish for falling for the social pressure not too.