Rey and Kylo are the twins of Luke Skywalker. Ill add background to my theory. The original trilogy and prequel trilogy have very strong paralells. These paralells are supposed to highlight the fact that you cant outrun your past. And you cant escape fate. For example. The mentor dies in epusode I and IV, there is a battle with a Fett and the Skywalker loses his hand in episode II and VI. The protagonist makes difficult choices and must face both the emperor and their father (Obi being Anakin's Father figure) in episode III and VI. These parallels aren't just lazy writing. They are actually quite smart at showing both innevitability AND to show that Anakin and Luke aren't all that different. So if you look at the new saga at face value, there doesn't appear to be too much room for parallels from the padt sagas. But if the writers and directors are doing thhir jobs right, they will continue with the connections to the past. Now let's look at the new one-sheet for The Force Awakens. There's been lots of talk at the location of Rey and Kylo, and how their weapons are shown parellel to eachother. Thats not the big giveaway though. That giveaway comes when you look just under the weapons, almost touching them. You see that yellow lightburst? The one that is almost radiating from the touching of Kylo and Rey's weapons? Now go look at the one-sheet for A New Hope. The one where Luke Skywalker is holding his sber over his head. What do you see at the tip of the saber? A yellow lightburst. A lot of "fanboys" like to make connections and quote padt stories... Novels, and comics, and the fact that they could be the solo children. But they aren't. Certainly not the same children you read about. And you need to forget everything you assume i still cannon just because there have bee. Source material to draw from. And though the Solo's having a family might make a bit of sense. Why? Its not like there is going to be a whole book series to flesh them out, or have their backstory as a highlight etc. Etc.. No if these characters ARE related, there needs to be a point. There needs to be a reason that decision was made. So what sense could thwir be of Luke having twins? Well there's that parallel to connect to the stories that shows a running theme. At the center of the main protagonists of the two movie teilogies is the theme of legacy and the relationship between father and son. That theme is undeniable. If you buy into that fact that Kylo Ren is Luke's son, it changes a moment we've seen in previews where Kylo looks upon the crushed visage of Darth Vader and swears to finish what "he" started. And easy as it is to take that at face value that Kylo, the red saber wielding knight of the first order, wants to uphold the ideals of the empire and looks up to Darth Vader... Isn't it at all possible that either: A) He's not bad at all, and is actually trying to take down the order from within. Or in all likelihood. B) is talking about reuniting father with son. Something Vader desperately wanted. Remember the earliest plot leak rumors revolving Luke? They stated that Luke went into seclusion because of his growing powers that were getting out of control and he was afraid for himself? Chances are. He like obi wan, wanted to separate the children to try and stop them from learning of their parentage and from stopping their potential "destiny". Likely Luke looked at him and his own sister and feeling his powers grow and intensify, worry that he is as his father was and may turn out evil, while Leia was the good child. So when he has his own kids, he separates the two. Why is that important? Again... Parallels. My guess would be that Rey is given to Han and Leia to raise as their own, knowing that she would be in the right hands and at least atill with family, and someone who could guide her While tge true mother of both, and Kylo's adoptive parentage would be a major plot point for the series. Also surving as a plot point and parallel to previous stories would be Kylo knowing of their relationship. In fact ita possible both know of the relationship but may think them cousins and not brother / sister. And it could lead to that revelation moment that not only makes a parallel to Luke and Leia's relationship, but that "I am your father" moment between Luke and Vader.