Before you scroll down to the comment section and tell me "It's not true, THAT'S IMPOSSIBLE!" hear me out, because there is a pretty compelling argument to be made. WARNING: THERE WILL DEFINITELY BE SPOILERS!!!
1. Luke being Rey's dad is too obvious
Like almost everyone else, when I first left the theater, I was convinced Luke was Rey's father. However, the farther I get away from that amazing night on December 17th, the more I think that this can't be true, mainly because it is way too obvious! Star Wars is known for its twists and turns and this just seems too straight forward. If not Luke, then who? There are some really good theories floating around the interwebs that Obi-Wan is her grandfather. There's a great post you can check out by Jack Car about how Rey could be a Kenobi.
2. Ben Solo's call to the light
What if this internal struggle isn't just because Kylo is actually a good guy deep down? What if his path to redemption is Rey, and he can feel her calling out to him via the force, and this is the metaphorical call to the light! I would actually prefer this theory than Kylo being conflicted because deep down he's a good guy. Darth Vader was not a good guy at all, but he was still redeemed because of the love he had for his son. Luke was his call to the light. Luke is to Vader, what Rey is to Kylo.
3. Their first encounter
Kylo Ren has Rey trapped, he toys with her, but doesn't kill her because he needs the information from her mind. That is all fine and makes total sense. The part that sticks out is when he knocks her out with the force and gently carries her to his ship. He doesn't drag her, he doesn't have his stormtroopers carry her. He carries her himself like a delicate little flower. Can't imagine Darth Vader doing that with anyone but Padme.
4. The interrogation
When I first saw The Force Awakens I was surprised by the strange sexual tension in this scene. I chalked it up to the actors having natural chemistry and that any of that tension was accidental. But was it? After all, Finn and Rey never had this type of sexual chemistry in the entire movie, that these two had in one short scene. Plus, Finn seems pretty deep in the friend-zone.
5. The lightsaber fight
This fight left a bad taste in a lot of fans' mouths because they couldn't see how Rey could defeat the trained Kylo Ren. There are plenty of theories on how she beat him, from Kylo being too injured after being shot by Chewie, to Rey having a superior amount of midi-chlorians. My theory is that Kylo had no intention of killing Rey. Yes, I'm aware he threw her into a tree, but during the actual fight there is a moment where Kylo has Rey at the edge of a cliff and could easily push her off, but instead he eases up and tells her that he can train her in the force. If you've seen the movie you know what happens next. Point being, even when I assumed these two were related, it didn't seem like Kylo wanted to kill Rey in their fight.
6. Bringing balance to the force
In The Force Awakens it is abundantly clear the force is in flux. The two most powerful characters we see are Kylo Ren and Rey. These two create the yin and yang of the entire new trilogy, and them coming together could potentially bring balance to the force, as Anakin was supposed to do in the prequels. Their kids could even be the premise of Episodes X, XI, XII.
If that's not enough to convince you perhaps this video will. You really see the parallels to Padme and Anakin!