Relativity

(Gen 28:2 KJV)  Arise, go to Padanaram, to the house of Bethuel thy mother's father; and take thee a wife from thence of the daughters of Laban thy mother's brother.

(Proverbs 11 also read)

Jacob was sent off to marry a cousin.  If you are reading fast and your stomach is growling, you might miss this little point.  In the culture of the day it was considered optimal to marry a cousin.  It should make you think twice about your jokes involving West Virginia.  The reason for this that I heard was that the human genome was not so corrupt in those days, which made the problem of interbreeding less.  In addition to that, you knew the genetic background of your cousin and you might not know that about some young lady that caught your eye on the street.

So?  That standard does not apply today but it helps a bit to understand the culture of the people in the Bible.