A false reality
Jean-Luc Riker was the son of Captain William T. Riker and Min Riker, born on stardate 50415, in 2373, and named in honor of Admiral Jean-Luc Picard. His mother Min died in a shuttle accident in 2381 when he was eight years old.
Jean-Luc also enjoyed fishing and picnicking with his parents in the holodeck's Curtis Creek holoprogram. On one fishing trip to Curtis Creek, he caught a fish that pulled him into the creek. His mom tried to net a fish and she fell in the creek, too. His dad then tried to pull the both of them out, and he fell in.
Throughout his childhood, Jean-Luc struggled with his father's Altarian encephalitis.
His father's relapse
In 2383, after having another memory relapse from the Altarian virus, Will was introduced to Jean-Luc without warning in the hope that such meeting would cause an impact to help him remember his son. It was on this day that his father spent time with him in effort to find part of what he had lost.
Jean-Luc was later injured, breaking his wrist playing Parrises squares in the ship's gymnasium after falling off the ramp. This caused Will to over-react, revealing his fears of being a father, noting how his own father had abandoned him at a young age.
As his father attempted to learn more about the last sixteen years of his life that were missing from his memory, he accessed his family record. After viewing a home video from stardate 58416, Will noticed something peculiar about Jean-Luc's mother, Min. Will realized that his 'wife' was, in fact, Minuet, a holographically-created 'fantasy' woman designed for him several years earlier by the Bynars.
The charade revealed
Once Will realized what was going on, the "future" scenario was replaced by a ploy created by Romulan neural scanners and a holodeck. The USS Enterprise-D, his mission, his wife and Jean-Luc were discovered to be the result of a Romulan attempt to locate the Federation Outpost 23.
Upon release from the Romulan holodeck, Will was introduced to his 'son', 'Jean-Luc', purported to actually be a child named Ethan, also held in the Romulan's custody, and whose image was used to augment the holoprogram. It was later revealed that Ethan, like 'Jean-Luc', was a false identity of an alien named Barash who masterminded the whole scenario on the planet Alpha Onias III.