Consanguinity ("blood relation", from the Latin consanguinitas) is the property of being from the same kinship as another person. In that aspect, consanguinity is the quality of being descended from the same ancestor as another person.
“We have appealed to their native justice and magnanimity, and we have conjured them by the ties of our common kindred to disavow these usurpations, which, would inevitably interrupt our connections and correspondence. They too have been deaf to the voice of justice and of consanguinity.” - Thomas Jefferson, The Declaration of Independence
Online today I came across the e-version of the Pocket Constitution Mr. Kahn was holding at the Democratic Convention. For 49 cents I couldn't resist. I'm pretty sure I read the Declaration of Independence in Junior High, but certainly not since.
I particularly like this in the context of our current tensions based on skin color. In light of what we now know about human origins and genetics, we all need to listen to the voice of consanguinity.