Rey is definitely not lukes daughter. Only if jj Abrams and all the other producers stick somewhat to the expanded universe. Han solo and Leia have 3 children. The first 2 are twins Jaina solo and Jacen solo. The youngest is anakin solo. Luke skywalker only had one son named Ben Skywalker. JJ Abrams has switched this completely, I don't know why, I think it's because Disney has taken over. But in SW episode 7 they have made Kylo Ren be Ben Skywalker, which is really the name of Luke Skywalkers son. So in the expanded universe luke does indeed train Han solos son Jacen solo (Kylo Ren) but in the expanded universe Kylo Ren is not his villain name. It's Darth Cadeus. So they've also given Jacen solo the wrong name. But to continue, Jacen like I said has a twin sister Jaina solo. When her brother Jacen gets seduced by the dark side. Luke trains Jaina (which is his Niece) she ultimately fights her brother Jacen and kills him. Also in the expanded universe Han solo does not die like he did in Episode 7. So to end the confusion, if JJ Abrams and Disney want to do starwars right. Rey (Jaina solo) should be the daughter of Han and Leia. Not Luke.