This is set in the same ‘verse as my fic
The L World, but all you really need to know for this is that in that AU Jack O’Neill is a ROG named Angus MacNeill. This is set at the end of the Stargate SG-1 episode Fragile Balance It's been sitting in my brain for a while, but
aeron_lanart spurred me into committing it to type.
None of it's mine, not one little bit.
Tipping the Balance
Jack sat and looked thoughtfully at his ‘Mini-Me’. It was all too beyond weird for him, but there was something they needed to talk about before they went their separate ways.
“How much do you remember?” he asked.
“Just about everything, Angus,” Mini-Jack replied. “There are a few gaps, but not much.”
“That damned Immortal memory, huh?” Jack said with a smile that he didn’t really feel.
The pair fell into an awkward silence, Jack looking out the window and Mini-Jack staring at his shoes. Jack watched as a mother walked hand in hand with her toddler. Sitting next to him was what was essentially his only shot at having a son of his own. Suddenly he realised why Immortals couldn’t have children, and he turned back to his clone.
“Is it there?” Mini-Jack asked before Jack could speak. Jack briefly contemplated playing dumb, but he knew exactly what his clone was referring to.
“No. Whatever it is, Loki couldn’t, or didn’t, clone my Quickening. You’re mortal,” he answered. “I’m sorry.”
“Sorry? Don’t be. Now I get the chance for a normal life. To have kids, grow old and die with the woman I love. All the things I know you regret not having,” Mini-Jack replied.
In that instant, Jack could see his four thousand years of memories in his clone’s eyes. He was both envious of the boy and pitied him. To live a mortal life, with all its fragile joys and pains. Depending on which day of the week it was he would either gladly trade everything for it, or not wish it on an enemy.
“So, this is goodbye then,” Mini-Jack said, rousing Jack from his thoughts. “After all, there’s a reason Immortals don’t have kids.”
“And you don’t want to see me, it’d be too weird,” Jack added with a smile that was genuine this time.
“Definitely too weird,” Mini-Jack replied.