Quote Originally Posted by Pntbll248 View Post
You could always look towards arguments regarding natural order. I'm not a huge fan of natural order authority myself, as I believe humans are free moral agents who are free to defy their own nature. But, as a quick synopsis: Things ought to behave according to their nature. Humans naturally form mating pairs with the opposite sex, thus all humans ought to form mating pairs with the opposite sex. Quick notes: Doesn't apply to things like cars and medicine (ie, you can't disqualify the natural order argument by saying that cars are not natural so therefore we shouldn't use them) because tool use is a natural trait of humans. Also, if humans naturally make free moral choices and are not bound by their nature, then this argument falls apart.
(emphasis added)
Forgive my ignorance, but could you back the bolded bit up with something? Because as it stands, the assumption doesn't seem justified in my eyes. This of course delves into the definition of what is "natural", which is still up for grabs. If we take natural to mean something that is readily found in nature, then this natural order argument doesn't work.
And as a follow up question: What reason is there to think that what is natural (whatever definition you're using) for some humans should also be natural to all humans?

For Wicked, this video pretty much sums up any and all arguments I've heard against same-sex marriage, secular or otherwise: http://www.youtube.com/watch?v=lSfFa44p96o
Alas, the arguments are very simplified (maybe overly so) for the sake of emphasis. But any argument that I've heard so far can eventually be boiled down to one or several of the points made in that video.