John Sheppard was twelve years old before his parents told him he was adopted. His relationship with his father never really recovered from the blow of betrayal inherent in the words, "Son--you're not ours."
It explained a few things, at least, like where his hair came from (both his parents were blond, though his mother tended to have slightly mousy roots) and why he was so smart. But the thing was, they didn't know whose he was, so he ended up defining himself by whose, and who, he wasn't.
Twenty-two years later, he's still putting distance between him and them, trying to get far enough away to find himself.
Elizabeth Weir got a tattoo when she was twenty-two, on the inside of her wrist, while she was at the Swiss academy that she had convinced her parents was a finishing school, but was actually a ton more interesting. Unfortunately, the organization that employed the graduates proved rather boring--for her, at least. It was still an old boys' club in many ways, and she couldn't break in. She had the tattoo removed before she came back to the United States, because she didn't really want to have to explain it to her parents. She felt pretty foolish about the whole thing. She figured she was young, and she was allowed to make a few mistakes.
She never thought her mistakes would become so important when she was all grown.
Carson Beckett was studying the ATA gene long before it was called that. He called it the L gene for longevity, though he hadn't published what he thought it was truly capable of. He was trying to prove it could arrest aging if properly triggered, and had already engineered a vector to deliver the L gene to the cells of non-carriers when the American Air Force, accompanied by enough of Her Majesty's forces to make it legal, waltzed in and declared his research classified.
Then they sat him down and explained what they knew about the purpose of the gene, and where they wanted him to go, and what they hoped to find.
Carson breathed, "Atlantis?"
"City of the Ancients," confirmed the colonel briefing him.
Carson was hooked.
John's chopper went down in Afghanistan in 2002. Mitch and Dex stayed down with it. John walked away without a scratch. He still doesn't know why, and he tries not to think about it too much.
It was just one more thing to run from. He'd run halfway around the world, easterly, and not outrun everything he didn't know about himself. The Air Force offered him Antartica or discharge; he took Antarctica because he'd never run south.
Even Antarctica wasn't far enough away, but that turned out to be less of a problem than John would have thought.
Elizabeth froze up on the examining table when Carson took her hand to look at her wrist. He wasn't the first doctor to notice the scar there, but it always made her nervous. "It's not what you think," she said. "They wouldn't have given me a project this classified to run, if it was."
"Hmm?" said Carson, "Oh, no, I didn't think that at all. It's entirely the wrong shape." He didn't let go of her hand, though. "A burn? Too neat... it almost looks like you used to have a tattoo, but that's a nasty place for one--painful."
"Painful to get it taken off, too," Elizabeth admitted.
Carson blinked at her. "Dr. Weir," he said, because they hadn't know each other very long, "I think there's something you should know about my research."
That evening, Elizabeth called up an old friend from school to ask for a few names--a few recommendations for scientists in various fields, who were peaceful enough to work together in a closed environment without taking each other's heads off.
If Stargate Command was surprised at how many of Elizabeth's requested staff had the ATA gene, they didn't mention it.
Rodney McKay wanted to have the ATA gene more than he'd wanted anything in all his thirty-two years, but Carson put off giving it to him because he didn't know what all the effects would be. If it did work as a longevity gene--well, Carson didn't know whether to hope it did or it didn't. He knew a few people who'd rather kill themselves (and him) than face an eternity with Rodney.
On the other hand, the ramifications if the gene therapy worked...
The ATA--the Ancient Technology Activation--was easy enough to test, and it apparently took. The longevity, Carson couldn't think of any way to safely test but with time.
He didn't tell Rodney, because he was afraid Rodney would be too impatient for that, especially after John tipped Rodney over a balcony to test out some silly little shield device. Carson shuddered to think what might have happened if it hadn't worked.
What might have happened, or what might not have.
Carson Beckett is six hundred and twelve years old. He was born (hatched? delivered? created? this question still troubles him) in the latter days of the plague in Europe, when there were empty towns dotting the landscape, and everyone knew someone who had died. When he was young, this seemed a terrible thing to him, and it drove him to become a doctor, to try to stop the suffering and misery. When he was older, eventually everyone he knew died, but it never stopped seeming terrible.
If he can make the L gene work, if he can give it to everyone, then someday they'll all be immortal, and no one will ever have to die.