Elizabeth Marquardt makes one good point: once we abandon the core reality that marriage is the union of husband and wife, what's to stop "group marriage"?
Is the prospect of group marriage far-fetched? Probably not. There are several avenues that could soon lead to legal recognition of unions involving three or more people. The efforts come from the fringes of the left, from the darkest corners of the fundamentalist right, and from the laboratories of fertility clinics and hard scientists around the world.
... Get ready for the debate. And in the meantime, wedding planners: start figuring out how many brides and grooms you can fit down that aisle. -- Huffington Post