There's no sin in having it done today, but if you're doing it to be saved then you're doing it wrong.
March Madness, though?
I read an article in a Christian magazine a while back that said that back then, marrying your sibling was okay, no genetic harm done. But by the time we had the children of Israel on the scene, man's genetics were in danger of degrading so you had to start looking further afield.
Something like that. I saw it years ago and this is off the top of my head, hope I made SOME sense….