A semi-recent schtick with the whole same-sex marriage/sex debate is that the Bible is not inerrant, and thus any and all teaching about the sinfulness of same-sex marriage/sexual behavior must go out the window. Instead, whether or not these things are a sin must be determined by "empirical research" - namely, either these things are shown to be harmful, or it's not a sin. Note that this claim is coming from proclaimed Christian quarters, typically "progressive", along with the insistence that God would never give arbitrary commands, etc.
There's a lot wrong with this. The very claim that the Bible is not inerrant, or even so errant that we can't trust the moral teachings. The idea that God would never give a command that we disagree with or don't understand. The idea that God only commands things that make us happy or benefit us empirically. Perhaps worst of all, the reliance on sociological and psychological studies as 'empirical evidence'.
For now, I just want to point out something I've noted in the past: notice that the 'The Bible's not inerrant, therefore we have to throw out this teaching!' never gets much play for the commandments, or even the mere inferences, people actually *like*. Admonishments to give to the poor, to turn the other cheek, to be forgiving, to do this or that - the very act of questioning the validity of these commandments 'because we don't believe the Bible is inerrant' doesn't seem to register. No, of COURSE God would command us to do this or that, and the Bible's being inerrant doesn't matter because... well, we can just feel this is what God would do.
Now, I find the idea of determining the sinfulness of general actions by looking at statistical data from the softest of the soft science to be insane. I think metaphysics, philosophy and other areas are king here. But, I do have a simple challenge for anyone who plays the 'empirical study determines sinfulness' card.
It's simply this: tell me that if I or others think that the empirical data determines same-sex marriage - or same-sex sexual acts - to be sinful, that it provides justification (if only for those who agree) to treat such things as sins.
If I look at the open marriage rates of same-sex couples, if I look at the suicide rates, the psychological profiles... if I use what I regard as reasonable 'empirical' metrics for these things and it looks like it turns out to be 'sin' after all, then I and others who agree with me have shored up, in some way and to some degree, the view that these things are sinful.
I ask this, because I have a suspicion: this possibility, like the possibility that the errant Bible does NOT teach Christians to be generous, or kind, or turn the other cheek, or this or that, is not accepted. It isn't a "live option". The demand for empirical evidence is purely a formality, because what the empirical evidence shows or can show has in advance been decided upon. But intellectual honesty and consistency demands the possibility of being wrong on the empirical front - and disagreeing about what the empirical evidence shows is damn common.
To bite this bullet would be to open up the possibility of these things being 'non-sinful' by that metric, only at the cost of likewise opening up yet another route for people who think such things are sinful to defend their view through.
But to try and argue that the empirical evidence only points one decisive way in the flimsiest quasi-scientific fields would be an obvious joke, and yet more evidence of insincerity. The critics of same-sex marriage and same-sex sexual behavior can deal with disagreement on this front far better than their opponents.