Nice to see that I wasn't the only one who enjoyed Supernatural :-) Not that I'm letting my fragile broken heart trust that it'll stay on air now that I've decided I like it. No, siree. You fooled me four times once, but you're not doing it again. I shall enjoy it while I can and take each week as it comes.
I'm interested in how the fic's going to play out with the incest taboo in the mix (that's not a spoiler, btw; the brothers aren't involved on screen).
Because the brothers are the only characters we're going to get to know well if the show falls into the pattern of them going to a town following the messages left by their father, dealing with a supernatural threat and moving on, most fic is going to focus on them. The ending of the pilot has shown them that a normal relationship and a normal life isn't theirs for the taking (and I find it interesting that the girlfriend and the mother are both physically very similar; wonder if that'll factor in or if the girlfriend was safe right up until the moment that Sam returned to the fight?) so what are they left with?
Well, each other. But from what we heard on the show, it's always been that way. These two grew up being trained from an impossibly early age to be 'warriors'. They knew there was a world outside the mundane full of scary monsters.
They really aren't going to the the kids you invited over for sleepovers or PB&J sandwiches.
They grew up in a masculine household; I seriously doubt their father ever dated, and they clearly, Dean especially, view themselves as outside society's rules; they have a mission, and they'll break any laws needed to complete that mission.
It's significant that Sam wanted to become a law student; compensating/rebelling against that maybe?
There's nothing on the show to suggest that the brothers are sexually involved; Sam tells the Woman in White that he's never been unfaithful, which means I suppose that there was no 'good to see you, bro' sex in the shower/motel room although I found myself mentally writing some. That's not going to stop it being written though because it's just too tempting to slash them.
If they'd been friends, I think the urge to slash would be one most slashers would give into without hesitation; two pretty boys, fighting the good fight, risking all to save each other, with buckets of angst and snark and simmering resentments and tension and protective possessiveness; God, it's perfect.
But the brothers bit is going to squick some people and I get that. I read too much Heinlein at an early age not to be able to give it some objective thought, but yes, the idea of it produces a cultural knee kerk of 'no, wrong'. But there aren't many reasons why they _shouldn't_ turn to each other for sex as opposed to one night stands to relieve the tension....
They're close; Dean's protected Sam from the start; the older brother who's there to turn to. There's no biological reason why they shouldn't have sex, being both male, and they're both unlikely to care much about the legal aspects of it. They're, Dean especially, isolated from society. They have no one who can understand what they're going through; notice that Sam was prepared to marry his girlfriend (sorry; hopeless on names..) but wasn't ever planning to tell her his secrets.
They can't open up to anyone but each other. They can't love anyone but each other, not without feeling guilt that they're putting them at risk.
Sex with each other is the safest sex of all for them. It's pretty much all they've got.