"If homos have a constitutional right to marry, why don't siblings.??"
Because marriage is a union between two consenting, adult, and equal partners not related to each other in a relationship recognized by the state – same- or opposite-sex.
Given the return of this and similar moronic threads, clearly the Obergefell sitzkrieg is over.
People are related to each other marry all the time.
If we go by the Bible or evolution everyone is related if we go back far enough.
*****SMILE*****