Q&A: What Is the Reason for the Prohibition of Incest?
What Is the Reason for the Prohibition of Incest?
Question
Hello Rabbi,
I wanted to ask an interesting principled halakhic question:
Suppose two pairs of identical twins marry each other (a brother with a sister, and his twin brother with her twin sister). The children of the two couples would be cousins, but genetically they would be like full siblings.
From a halakhic perspective, are those cousins considered ordinary cousins, who are permitted to marry one another, or should we also take the biological closeness into account and view them like brother and sister?
Answer
They are like ordinary cousins. And in general, you are assuming that the prohibition stems from genetic closeness (harm to offspring?), and that is not necessarily so.
Discussion on Answer
??
David, you didn’t read the question and mistakenly thought that Oren was asking about a brother who married his sister, but that is not the case. Take another look at the question.
They are mamzerim, not ordinary cousins, and therefore they are forbidden to marry