Reply To: If you marry your first cousin

Iaskern; That’s an old sugya (in Yevamos?) known as “I am my own grandpa!” Of course that’s when both of those couples have children. That’s when you need to have a bottle of Tylenol ready when you read through the ensuing family tree.
Though not qualifying for your extreme example, reading a description of the intertwining marriages of the Skverer Twersky’s and the Vizhnitzer Hager’s would require the bottle of Tylenol at hand as well.