There are several, it depends on your reference frame, and it doesn't require religion be in the mix, the Soviets weren't too nice to queers even after the idea that it was some psychological malady had been debunked. I'd warn you against assuming the opposition's quiver is empty, on any given subject that's a good way to get your rhetorical ass kicked. One of the more valid points is that marriage represents a 'positive right', which it really does in many places, as opposed to a negative right, which is how we generally argue for it. Under that the primary justification for it gaining benefits is that it helps society, because as a positive right it requires something from society, as opposed to negative rights which require little to nothing from society. Where special privileges exist for anything, those expected to help foot the bill generally feel that they are, for lack of a better term, investors who feel they should have some say in the concepts, principles and methods behind that privilege they are footing the bill for. I get to skip this section because I don't believe marriage should be a positive right, however I'm in the minority, big time, on that one. Where it is a positive right it doesn't just carry certain things like name change and default next of kin but whole volumes of official and unofficial privileges and responsibilities, and after centuries of legislation where everyone 'just knew what it meant' most state legal codes include lots connections and rulings to it off that common unspoken but obvious definition to the point that you'd need half a ton of C4 and the jaws of life to tear it free. Don't make the mistake of over-simplifying this sort of thing. There are few if any valid arguments against gay marriage when marriage is a negative right, but when it is a positive right they start popping up like corn in Iowa and have a fair degree more validity.




That's an oversimplification, most societies have been dominated by knowledge and tradition, religion tends to be wrapped up strongly to both because we generally believe that people who know a lot of stuff tend to be right a lot more. Old Snerg who always knows when the rain will come and taught you how to plow a field easier is to be respected and believed even if he thinks he can predict the weather because the Rain God sends his bones messages and that the angle of the plow blade is most effective at 27 degrees because 3 is a Holy number and the Earth God is most pleased by 3x3x3 and let's the blade pass with the least objection. Most smart people got that way by seeking The Ultimate Answer, and generally landed on something 'less not right' then the average Joe, and we tend to respect that, if Stephen Hawking came in to a room and declared that "Because of Quark-Moron Plasma the Universe is spreading into a toroidal, donut shape" most people would nods there heads at this wisdom and go forth to spread the word of the impending Donut-verse, pre-science there was virtually no difference between religion and knowledge, since then its still pretty close to the same thing, that's why so many famous scientists were mystics, clergy, etc. and people go along with this because the wise old shaman is to be trusted whether he's dancing around in feathers and throwing bones or wearing a clerical collar or a lab coat... usually a smart move too.



Mostly we live in a society where travel and communications are so routine, and nations are so large, that we just codified people's right to follow their own traditions wherever it didn't seriously harm the collective, because people had to interact with huge amounts of differing local customs. In the US, that separation was primarily to protect various religions from the state, not to protect people from religion, as you're implying. And a pretty fair amount of religious persecutions started up because someone was challenging the state's authority, we've seen the same from Atheist states directed at those who challenged a piece of science they'd invested in, see "Lysenkoism".



Euclid's Axioms on Geometry are also 2000+ years old, so are Aesop's Fables, the only reason a book or work's age is relevant is that if something has managed to keep getting cited after centuries, it probably indicates it has some value and merit, and I'd appreciate if you'd not imply I'm irrational, that you can't understand 'how any rational person could believe in such things' strikes me as a problem you should be seeking to address, because a pretty good chunk of the people most would regard as champions of reason believe or believed in such things, and I'm not sure how the breakdown goes amongst scientists but I don't know many in my own field of physics who consider religion at paradox with science and reason, regardless of their own beliefs or lack thereof, and maybe it's field arrogance but while we claim no monopoly on the faculty of reason we're generally considered to have more than our fair share of it. Even when I was an atheist, and later an agnostic, I never considered those who weren't to be prone to being irrational or possessed of impaired reasoning abilities, if you think that's the case, I'd respectfully submit you should re-evaluate either your definition of 'rational' or your definition of 'religion', and barring that at the very least I'd appreciate if you'd have the courteousy not to lob insults at religion when I did not invoke it as part of my comments, but again only mentioned it when someone also threw a slur at it.