The recognition of same-sex marriage is, of course, the next natural step in the evolution of marriage into what it is today -- a legally recognized status of companionship between two people. The mere fact that we, unlike in the vast majority of premodern societies, each choose our own spouses is case enough for same-sex marriage. Marriage is now a relationship one can enter with anyone one chooses, regardless of class or race, yet this was of course not always the case. Removing sex as an exclusionary category would merely reflect what marriage has already become.
But of course, many people don't see it that way. Most simply have a prejudicial disposition toward gays and lesbians, and though they have largely given up on excluding them from other rights and privileges (like employment) because those battles in the culture wars are seen as lost, marriage is still viewed as a fertile battleground, and so preconceived prejudice toward GLBT individuals takes the form of sometimes highly overwrought rationalizations against same-sex marriage. Nowhere is this found more often than in appeals to polygamy.
Some people just don't seem to get that limiting the number of spouses one can have is not the same as limiting whom one can choose to marry, so I thought phrasing it as a math problem might help. Of course, given our level of mathematical and logical knowledge in this country, this may prove all for naught. But I thought it would nicely illustrate the point nonetheless.
Let's of course assume that M = male and F = female. Now today, men and women are (supposedly) equal, so we must therefore assume that M = F, whatever value we assign to them.
Opponents to same-sex marriage routinely (and ad nauseam) proclaim that marriage should be 1M + 1F. Signs illustrating this unproven assertion often suggest Marriage = 1M + 1F. But given that the genders are (again, supposedly) equal, we must then assume that if 1M + 1F = Marriage then 1M + 1F also = 1M + 1M, and 1M + 1F = 1F + 1F. Because M = F, then the equation holds true. Let's say we assign the value of 1 to both M and F. Thus 1(1) + 1(1) = 1(1) + 1(1). See?
But under no situation can you make 1M + 1M = 1M + 7F. The quantity is, of course, what makes the difference, unless you want to assign different (unequal) quantities to M and F. Of course, this is indeed at the heart of much of the anxiety over same-sex unions. Opponents to same-sex marriage routinely suggest that all children deserve both a mother and a father (fallaciously implying that children are a legal prerequisite to marriage), and thus must have in mind the notion that a father has a specific role and a mother has a specific role, an assumption that hardly fits the changing character of our family structures, where increasing numbers of men are raising children in the home while women are the bread-winners. To many of those suggesting mothers and fathers have specific roles, M ≠ F. For the rest of us, surely in this day and age we can assume they are equal.
If they are equal, then stacking up seven wives in one marriage and calling it the same as a partnership between two people does not produce a logical comparison. Such comparisons are therefore inherently, demonstrably flawed in logic, and should be retired by those who regularly make them.
But don't hold your breath.