re: #335 buzzsawmonkey
I don’t know if people in ancient times understood genetic problems long before they knew genes existed, as you claim. I do, however, know that the reason such unions as you mention above were expressly forbidden in the Torah is because otherwise people would have felt free to engage in them; the prohibitions exist precisely because morality is a limitation externally imposed upon otherwise natural urges.
Which begs the question … what was the reason that those particular natural urges required suppression in the first place?