- Fifteen years is a pretty long time in a relationship to not end up having children. Granted plenty of people choose not to but see how quickly he managed to come up with names and genders for his supposedly nonexistent kids. That's not the lying ability of someone who's not interested in it. Plus the other characters all have estranged children so he'd fit the mold he so desperately wanted to break free from if he's ultimately the same.
- Sick Boy and Renton are consumate liars, though... but yes, I think it's possible that he has at least one.
This entry serves as an Alternate Continuity to The Blade Artist and Dead Man's Trousers in which the four men (Renton, Spud, Sick Boy and Begbie) reunite decades later where they are now considered irrelevant in a world that values youth over the accumulated experience born through years of living.
Renton has bounced across various jobs, having long since accepted his lust for life, Spud is an author who makes ends meet but is incredibly bored with his current life, Sick Boy is dealing with the repercussions of not dealing with his drug problems and the various illegal things he's done and Bigby -against all odds- has finally made something of himself as an artist and come to terms with his past demons.
Unlike T2 Trainspotting, they're on somewhat better terms and decide, fuck it. They've got nothing to lose now and they might as well make a name for themselves before they fade away from society and life itself. The movie will even have a "Choose Life" speech much like the other two reflecting the changes of time over a single generation.
Choose living your life with no regrets. Choose going out in a blaze of glory. Choose life.
