The Heterosexual Revolution - New York Times: "Marriage has been in a constant state of evolution since the dawn of the Stone Age. In the process it has become more flexible, but also more optional. Many people may not like the direction these changes have taken in recent years. But it is simply magical thinking to believe that by banning gay and lesbian marriage, we will turn back the clock."
Gay marriage does not destroy marriage because you cannot destroy something so flexible and fluid. It is not a static invention that stands still, but a constantly changing and evolving social institution that moves with the people who live for now and for tomorrow.