Marriage is sanctioned by the state. Look at the laws governing inheritance. Go back to Roman times and follow the progress of laws forward. “Civil Unions” are a contrivance but they give to the parties virtually the same rights as partners to a marriage have. Yet two brothers/sisters living together ; two close friends with no sexual relationship are denied these same rights.
Marriage is for the establishment of BLOOD LINE INHERITANCE.
Gays do not reproduce. Therefore. there is no transfer of property to the next generation.
“Yet two brothers/sisters living together ; two close friends with no sexual relationship are denied these same rights.”
Familial relationships “Blood lines” are covered by long (Thousands of years) of inheritance rules, that vary by culture.
“Two close friends” have no rights, whatsoever, over familial rights.