Why just be concerned about "gay marriage"? We need a constitutional amendment that would allow either a supermajority of the state legislatures or a supermajority in Congress to overturn SCOTUS decisions.
I am all for the overturning of SCOTUS decisions that do not refelect the majority rule will of the people of the U.S., and run counter to what our Constitution says are 'states rights'.
Marriage is a state issue, so is abortion, until SCOTUS dreamed up the decision that they did, invoking 'privacy' into their ruling.
I would be more for an amendment that would limit judges in their ability to "make laws" instead of strict reading of the Constitution, which is their job. Legislatures make laws, Judges do not. Any laws judges have made, including MA same sex marriage, are in fact, not valid, and illegal.