The religious case against same-sex marriage can take many forms, and can be debated and debunked in many ways. But from my experience (quite a bit of it), these are the two quickest and most effective ways to debunk pretty much any argument against same-sex marriage.
1. Ask your counterpart what damage or negative consequences are actually caused by same-sex marriage, and what evidence they have to support their claims. Any objective argument against something must show that the thing has negative consequences, and that it should therefore be opposed, stopped, limited or at least frowned upon. If there are no negative consequences, there’s no basis for an argument against it. This still holds when the argument is based on moral or religious grounds, because these too must be intrinsically connected to actual effects if they are to be taken seriously. Every time someone poses a moral or religious objection to same-sex marriage, they’re making a claim about its real-world negative consequences (diluting the significance of marriage, harming children, destabilizing the foundation of society, etc.). And yet, always absent from every one of these arguments is any proof of actual harmful consequences. We’re always told that the negative consequences will become apparent in some yet to be determined future, but this is another way of saying that the evidence of harm does not currently exist. This is why I always ask my counterparts about harm in the present, rather than allow them to slip into some speculative rant about a dystopian future. Keep reminding your counterpart that same-sex marriage has been around in various nations and states for quite some time. If it had any negative consequences, these would not only have become apparent by now, they would have become empirically verifiable.
Show me how same-sex marriage has harmed the societies that legalized it. It’s been legal in Massachusetts for over a decade. It’s been legal in Holland for about a decade and a half. It’s been subsequently legalized in 20 countries. Enough with the hypotheticals, show me how it’s harmed these nations and states. Show me the before and after data, and point out how exactly these nations and states are worse off now than they were before marriage equality. And while you’re at it, show me how the nations that haven’t legalized same-sex marriage – let alone the ones that have strict laws against homosexuality – are doing better than the ones with legalized same-sex marriage. No more philosophizing, no more hypothetical hypotheses – the data has been in for some time now. Either support your claims or retract them! Put up or shut up!
2. Ask your counterpart what they think about adultery. It’s a very simple question that cuts right through the biased nonsense of any and all biblically inspired arguments. There are other questions you could ask, of course; questions about divorce or biblically sanctioned polygamy, but nothing quite reaches the height of adultery. Adultery is, after all, very strongly commanded against in the bible, the Quran and the Hadith. Moreover, adultery can – and often does – destroy many marriages and families in the here and now. So strongly is it opposed in the bible and the Hadith that it’s punishable by stoning to death. It actually takes center stage in the bible, with one of the Ten Commandments (the 7th) dedicated solely to adultery. It made it all the way to the Top Ten, in other words. Same sex marriage, or even homosexuality, never got that far. Adultery is much more of an important, forbidden and punishable sin than same sex marriage might be. It should therefore be much more strongly opposed and legislated against by those who keep clamoring about biblically inspired marriage laws – that is if they want to make a logically consistent case. And the fact that it isn’t, tells you all you need to know about the Cherry Picked subjectivity of the biblical case against same-sex marriage. If you want to base 21st century laws on Iron Aged, tribal Middle Eastern scriptures, you’ll have to do a much better job than that. And until you manage that, I’ll have to repeat my earlier statement about putting up or shutting up.