DarklordKyo said:
and that blood is generally thicker than water.
It's quite funny how this phrase has been taken out of context to such an extreme that it now means the opposite of its original meaning.
"The blood of the covenant is thicker than the water of the womb" is the full phrase. It means that those you CHOOSE to be with are more important than those you are associated to by family ties.
If someone in your family isn't happy about your life choices regarding your romantic partners then that family member, mother, sibling, cousin or otherwise, can go take a long walk off a short pier.