Most fans have been considering the fact that Luke and Rey may have a connection that there are a lot of other theories that go by unnoticed. It seems to be becoming more and more clear that Luke and Rey are not blood relatives. It could be possible that Luke followed the rules of the Jedi Order from the prequels and never got married or had kids, but what if Luke had a child who isn’t alive anymore.
Luke Skywalker did get married and had a son named Ben in the old EU material. So I would think that Lucasfilm would be able to find a way for him to start a family in the new canon as well.
We know that one of Luke’s students (believed to be his nephew Ben Solo) destroyed his new Jedi order. Mark Hamill and The Last Jedi director Rian Johnson have been teasing an old and bitter Luke in the film and there could be one simple reason that he’s so upset. Could it be possible that Ben Solo killed Luke’s son or daughter during his turn to the dark side? We don’t know what Luke has been up to the past 30 years and we have no idea how long he was trying to start up a Jedi order or even how many pupils he may have out in the galaxy somewhere. Kylo Ren killing his child would certainly make his exile make that much more sense and his falling out with the Jedi would seem a lot more natural.
Do you suppose that Luke Skywalker had a child killed by Kylo Ren?