Author's Note: I have an occasional headcanon that Sam is trans*, because queer headcanons are my favourite, and also because it actually makes a lot of sense, especially in the first few seasons.
{I}
John had always been happy that Sam was what he called 'low maintenance'. He kept his hair short, although Dad wouldn't buzz it for him like he did Dean's. He wore his brother's hand-me-downs, never complained when John bought exactly the same ten-pack of boxer-briefs in three different sizes. John praised him for his practicality, but sometimes Bobby looked at him funny, as if he could see right through him, and Sam just flushed and stormed away.
John never noticed what Bobby noticed. Dean noticed more than anyone gave him credit for, when he wanted to.
{II}
Sam's interest in research started when he was nine. The school he'd been in that month had a sex education class one afternoon, and as snickers and whispers ran around the classroom, Sam's eyes glued themselves to his desk. He didn't think he'd ever sweated so much in his life, not even that summer in Texas when he and Dean had slept in the backseat of the Impala for a week. The teacher shushed the class, trying to hide the croak in her voice as she pointed at pictures of growth charts and pubic hair. He hoped that the girl in front of him couldn't hear his uneven breath.
When he stole the book from the teacher's desk at lunch time, he'd never been so nervous. Not because he'd stolen something – no, he'd done that before, and he knew he wouldn't get caught. He just knew that something about what he was doing was... dangerous. Not dangerous like hunting was, but just as secret. He had to be as invisible as the freaks that stalked the oblivious world.
He hid behind the school building – the part where kids weren't allowed – between two big trash cans. Poking his head out one more time and seeing no one, he folded himself back into the niche and opened the book. He wasn't sure what he'd expected to find, really. It wasn't like any of this was exactly news to him – he knew what he looked like, and living with John and Dean in tiny motel rooms wasn't the most private. He'd seen his dad's badly-hidden magazines, and done enough unsupervised movie watching. But somehow this book just made it feel official. The illustrations were vague enough, but to Sam they were almost obscene. The 'Girl' diagram, cartoonishly drawn on a sickeningly pink background felt like it was designed to point out every single thing that was wrong with him - "breasts develop", "hips widen", "onset of menstruation".
He slammed the book shut, tossed it in the closest trash can and kicked the wall so hard he had to lie and tell Dean that he hurt himself playing football. His teacher never acknowledged that the book had disappeared. Sam suspected she was relieved, and he hated her a little bit for that.
{III}
For every day he spent in a library somewhere looking for outdated maps and vague mythologies, he spent an hour pouring over psychology textbooks and medical journals. What he found was pitiful, but he'd put more together from less before.
He never stayed anywhere long enough for anyone to question why he always used the stalls of the boy's bathroom at school. When he got to junior high, still no one questioned him. He was just the new kid again - some scrawny nobody from who-cares-where, and anyway he never stuck round long enough for anyone to get suspicious. But the best thing about junior high was computers. Much to John's convenience, Sam happily stayed at the school for hours after the final bell.
{IV}
When Sam was thirteen, he spent most of his summer at Bobby's, only occasionally seeing Dean and John. Mostly seeing no one, which was fine by him. He split his time between the one computer at the Sioux Falls public library, and the state directory, looking for any hospital or clinic that might have what he needed. He found three, and within a month, all of them had reported the theft of several apparently random items. The police concluded that it was random, just junkies looking for syringes, exactly as he'd expected them to. It was almost a pity that Dean and John would never get to see just how good Sam was.
{V}
One afternoon, John and Dean came back from a two-week hunt. Bobby was out, and Dean didn't knock before shoving the door to their bedroom open and throwing himself down on the bed he'd claimed years ago. Sam froze, syringe in hand and eyes wide, and before he could put it away, he heard Dean get up again. "Sam, what the fuck?"
Sam couldn't breathe, wanted desperately to explain, but all that came out was, "Dean, close the goddamn door." And something in his face or voice must have clicked, because Dean actually listened. Actually did close the door. He heard the trunk of the car slam closed. Thank god John was still outside.
"Sam," Dean continued. His voice had warning in it. "Sam, seriously, what the fuck is that?"
Sam briefly wondered whether lying was a possibility. Steroids, insulin, epinephrine, fucking heroin, he didn't care, because literally any lie was better than the truth right now. This wasn't even Dean's goddamn business, anyway, and what if he told dad?
"Don't you fucking lie to me, Sammy," because apparently Dean was a mind reader. "Don't you dare."
Maybe it was the fury in Dean's voice, or the inherent threat of John being called inside, or the fear in Dean's face, but Sam put the syringe down carefully on the small table between their beds. He glared at Dean, daring him to touch it. Dean didn't move. He reached under his bed and pulled the small pile of photocopied and printed pages from between the slats and the mattress.
He glanced at them, barely recognising his own hand-scribbled orderly notes and calculations covering every blank space. Dean took them, a picture of confusion and anger. He didn't read them all, never read anything as thoroughly as he should. But apparently he read enough to get the general idea. Sam simply say on the edge of his bed and waited, pulling the leg of his boxers down to cover his bruised thigh.
"Where'd you get that stuff?" Dean asked finally. Sam was so caught off-guard by the question that he answered automatically.
"I stole it."
And Dean. He'd be fucked if Dean didn't smirk a little. But then he reached for the syringe. Sam's heart pounded so hard he could hear it. This was it. He tried to level his stare, narrowing his eyes pointedly. Sam was a quick fighter, but Dean was twice his size and infinitely more experienced. He felt a bit guilty for expecting so little of Dean, for even considering that he might stoop so low. Anyway, he thought, a punch wasn't the most painful possible outcome.
Dean stood and his free hand cuffed around the back of Sam's neck, making him flinch. He closed his eyes, preparing himself for the real fallout, and felt cold plastic pressed into the palm of his hand.
Above him, Dean huffed one short, resigned laugh. "That's my boy."
{VI}
It wasn't a special night, but to Sam it became everything. John and Bobby were having some kind of row, and Dean had taken Sam by the wrist, picked the worn mitts from the cupboard under the stairs, and pulled him outside. The sun was setting, glowing dimly on the dirty white ball as it sailed between them.
Dean flicked his hand, directing Sam a few car-lengths away, before tossing it easily. It was just a little off-centre, but Sam caught it, pitched it back. Only the occasional instruction from Dean broke the silence – bend your elbow, show me your grip, better, eyes on the ball.
Dean threw the ball just as the familiar growl of the Impala sounded across the yard and they both turned towards it. The ball smacked Sam in the right shoulder, just hard enough that it sent a pang down his arm. At his small, "Ow," Dean turned back around.
He opened his mouth, and Sam expected mockery, but nothing came out. Instead he just stood there, looking at him strangely.
Sam frowned. Asked defensively, "What?"
Dean just shook his head. "Nothing," he lied. Sam was used to it, knew that something was wrong, that Dad had fucked up again, and also knew that Dean wouldn't talk about it. "How's your shoulder?"
Before he could answer, Bobby's voice boomed across the yard, calling their names. Sam just shrugged at Dean, mumbled something, and picked up the ball as they started walking towards the house.
As they walked, Dean slung an arm around his shoulders. "You got an arm on you, kid," he said, briefly tightening his grip.
Dean's arm around his shoulders felt heavy, and he wasn't sure what the hell possessed him but he said, "Kinda like having a little brother, huh?"
He tried to laugh, but Dean smiled the most disconcertingly clear smile Sam had ever seen. He covered the top of Sam's head with his mitt. "Yeah, Sammy. Exactly like having a little brother."
And that was it.
{VII}
After that, Dean and John were gone for a full month. It was the longest he'd been without them. They called occasionally, and Bobby and Sam passed the phone between them, sharing whatever information they'd dug up. Bobby handed the phone to him every time the word 'net came up. This was as useful as John would let Sam be, and despite himself, he desperately wanted to prove that he could do it.
Dean would tell him he should count his lucky stars that Dad let him stay at home and blow dust off books, instead of throwing himself constantly at things that wanted to kill him. But he knew that Dean was lying – that Dean actually loved the physical hunt and grumbled ceaselessly when he had to even touch a book. He also knew that John was keeping him out for the wrong reason. Hunting was a man's job, as far as John was concerned – one for which Sam was inherently unqualified.
And he would train him to fight, to shoot, to see everything that normal people didn't, but he wouldn't put him directly in harm's way. The worst part was that he never admitted it out loud, just mumbled something like, "Too young," or, "Two's enough," or, "Dean's stronger." It was insulting to all of them, really, to Dean, to John, to every bad-ass woman his dad knew. But it was a kick in the gut to Sam, every time. Maybe, he thought. Maybe if John said it, said that, Sam could object, argue, prove him wrong.
But he never did.
{VIII}
Over the time that they were away, Sam grew three inches. His chubbiness was less noticeable, his muscles more defined, voice deeper. Bobby hadn't said anything, and while he was wary of the day that he might, he was also thankful for it. He left town only once to commit felony theft, and all Bobby said when he got back after dark was, "There's a sandwich in the fridge."
Then Dean and John came back, and while he was happy to see them, he also dreaded the questions to come. He stood next to Bobby on the porch, and Bobby placed a hand on his shoulder and nodded once.
"Look who's finally hit puberty," Dean yelled, pushing Sam's head playfully as he traipsed past him, into the house and directly up the stairs to their bedroom. He mumbled something in response as Dean left, and out of the corner of his eye he saw John tense, heard him inhale. He didn't do him the honour of bothering to look up, didn't want to anyway, just waited for him to leave, too. Bobby's hand tightened on his shoulder just a little, comforting and steeling him.
"John," Bobby said, and Sam was surprised to hear warning in the greeting. Finally, Sam looked up, figured that if they were going to do this, he'd damned well be looking John in the eye when they did.
"You did good, Sammy. We ganked 'em all," was all he said. His hand clapped the shoulder that Bobby wasn't holding as he walked past. And Sam hated himself for it, but the praise still felt good.
{IX}
The day Sam said he was leaving felt like it would be the last time he ever saw his father. The fury of that fight was somehow worse than any physical fight he'd ever had. Neither of them raised a hand, or drew a weapon. They just screamed, everything they'd never said, everything that would hurt the most.
Dean watched, yelled, kicked the wall, and left.
After that, there was silence. Sam picked up his duffel and walked slowly to the door.
As he opened it, John said, "You leave now, and that's it."
As he closed it behind him, Dean said, "I guess you finally found the balls."
Sam wasn't sure whether it was a joke or an insult, but it was that which rung through his head two hours later when he punched a wall until he bled.
{X}
Dean broke into his house, Jess was killed, and suddenly they were looking for Dad. Driving directly towards every damn and damned thing that Sam had left behind, that had, of course, caught up with him. And without John, it was kind of easy to forget why he'd been so desperate to leave. He and Dean got along, and honestly he didn't think he could have made it through Jess's death without him.
They didn't talk about it, about his transition. Dean never asked; Sam never offered. He figured that one day they'd have to, but for now, with dropping out, with Jess and Dad and Yellow Eyes and the visions and maybe the end of the world? He had enough shit to deal with.
John said, "All I worried about was keeping you boys alive," and Sam froze. He listened to the rest with what felt like a thousand pounds on his chest, biting back tears he knew were there. He waited for John to finish, before begrudgingly beginning to accept the closest thing to an apology he was ever going to get. This wouldn't make it better, but maybe this time it wouldn't make it worse.
"We probably have a lot more in common than just about anyone." He sucked in a breath, waiting. For the first time since Sam could remember, he didn't feel a fight coming.
"I guess you're right, son."
It hit him almost physically, the way John said it. Deliberately, and with a smile that looked dangerously like pride. And maybe. Maybe aside from the demons and the visions and the world probably ending, maybe something good was salvageable after all.
Dean burst in, producing a jar of blood, and Sam hoped that he'd live long enough to try.