For those who think polygamy is A-OK, allow me to offer a brief dissent: Islam and the Middle East, where it's ok for cousins to marry.
I would never think of it. By the same token, I would strongly advise against marrying a woman who has a half dozen sisters. From personal experience, there's more drama than several soap operas. LOL, I love my in-laws, but you feel like you're being trapped in a Borg-like existence at times.