Jeff watched with bated breath as the effects of the tampering with the Chronivac began to take hold. In the short time he had rushing down for dinner with the family, the now beefy Mediterranean teen hunk had shifted his brother to the place where his mother had been. The first of the changes was the sudden memories flooding into everyone's heads at the table as the family tree began to distort.
Upstairs, the Chronivac whirred, first creating a whole new branch of the family tree. The machine's fans raced as it used all its processing power to insert family members into Derek's lineage, matching and testing by brute force to find combinations of men and women that would yield a result similar to the young man downstairs at the table. To all but Jeff, it was a completely normal dinner. But, to Jeff, he grew a little uneasy as he watched the subtle shifts in his brother. Derek's skin darkened, then lightened, over and over, the Chronivac iterating continuously, trying to find as close a match as it could. His shoulders broadened, then slightened, until finally settling into something similar to the 'new' Derek, albeit, slightly squarer, more proud.
Memories flooded into Jeff's head, tales that his new 'dad', that was still his younger brother, had told him of his youth, Derek Reyes was a soccer prodigy when he was young. Fast, strong, fierce. Jeff had to admit, the Chronivac's handiwork was exceptional...
Then, the process of aging the young boy into a man began. Derek's frame crept up, 14 became 15 then 16, the same as Jeff. The teen was astonished... and slightly aroused, at the sight of the young man his new-new brother would've been at his age. For as thickly muscled as Jeff was, Derek was even more impressive. The boy's tanned, olive skin and strikingly angular, handsome look, his stubbled jaw, all screeched the power of a youthful alpha male. Jeff's head swam as more new memories of the stories his father, Derek, had told him. By 16, the young super star had 'outgrown' soccer, or football, or even American football. "I was too strong," he would laugh, his deep baritone reverberating through Jeff's skull. The teen shuddered to think the kind of man that voice belonged to. But, from the way his now older 'brother' was growing, he was about to find out.
Jeff had become quite the specimen himself, 16 and built like a professional bodybuilder, gifted with an 11" dong. And looking at the massive 20-something male that Derek had become, it was a promising look at his future. It was at this time, in college when Derek had met Elias, or so the story went, according to his dads. Derek had taken up bodybuilding recreationally at the time, and Elias' stares at the campus gym were hard to go unnoticed. Or so the story went, the details were hazy as the two fathers often got too... excited to finish the tale. It was a nice glimpse into what Jeff would become, if the teen thought his dick would stop at just 11", the tents his dads pitched in their trousers when they were around each other begged to differ. With any luck, Jeff would soar past the footlong club like his fathers...
As Derek continued to age, he grew bigger, more muscular, more powerful. That recreation of bodybuilding became an obsession, one that his husband, Elias, was all too eager to feed. They settled down, and that's when Jeff and his mother came into the picture. The woman that sat across the table from Elias was still his 'mother', but now only in the biological sense. Memories changed in his head, the slender, toned woman and the pretty girl were now part of Jeff's surrogate family. DNA from both his fathers were implanted into an egg and implanted into the woman who now was smiling gently at him, the warm memories of his mom fading from his mind, replaced with a cold, more platonic relationship.
"Dear, pass the potatoes," Derek grunted, the boy now fully grown into a man. Jeff gulped as he looked at his 'new' dad. He was a freakin' beast! Though he was only an inch or so taller than Elias, he had to be almost twice as wide. Where Elias wore a nicely fitted, sporty shirt, Derek's had the top few buttons undone just to fit his expansive chest, the dense black body hairs bursting out.
Jeff coughed, catching himself staring just a little too long at his father, Derek. The 16 year old, excused himself and rushed up the stairs, doing his best to hide the 11" erection that ran down his pant leg. Goddammit! He realized a little too late that making Derek his dad had altered his own 'preferences.' He had to admit that he probably already had those tendencies, but turning both his dads into muscular, hairy men had really altered what he found attractive.
Jeff moaned as he sat on the edge of his bed and began to fondle at his length through his pants. His eyes went wide as he felt it... increase in not only length, but girth as well. He guessed being the product of two prodigiously endowed men made him doubly so. Wincing, he pulls the basket of his underwear out and his eyes practically bulge out of their sockets. That was his cock?! It was immense!
He begins to tug at his length, groaning as he closes his eyes, feeling the way his shirt gets tighter around his muscles. The Chronivac was finalizing the transformation. When he opens his eyes, the shirt he was wearing had changed, from a large to a XXL, and it was 'shrinking' or rather, he was filling it up. Jeff huffed lowly as he sees his big, almost pillow-like pecs fill the lower field of his vision. His chest spills out of the shirt, much like his larger dad, Derek, did now too.
His arms began to feel uncomfortably tight in their sleeves and the fabric begins to stretch and strain, struggling to keep all that muscle in... As Jeff's huge cock begins to sputter his load into his underwear, which had transformed into a jock, the now hulking teen realized that perhaps he shouldn't have changed his family tree to have two genetically 'gifted' fathers and a surrogate mother from who's stock sired big men as well...