Rey is born from the force. I know it might sound crazy but just listen to what I have to say about it.
Now we find Rey on a planet called Jakku and there we see she's like a scavenger hunting for parts to get food. Now doesnt this remind you of someone. Thats right Anakin Skywalker, he would always be looking through parts to build his pod racer. Also we find him on a planet that has a lot of similarities to Jakku.
Now we learn in the Force Awakens that Rey knows a lot about ships and can even fly them, just like Anakin. Another thing we learn is she can pick up on the Force super quick with zero training just like Anakin did. Now Im not saying there related but related through something greater than Parents. Thats right, the Force. Even the title of Episode Vll tells us the Force Awakens. Meaning now that Rey is born a new child from the Force has been born or awakened.
As George Lucas puts it "The story in 'Star Wars' is a classic one. Every few hundred years, the story is retold because we have a tendency to do the same things over and over again. Power corrupts, and when you're in charge, you start doing things you think are right, but they're actually not."
Now what he's saying is everthing always has a pattern like Star Wars so he's repeating the story with each trilogy just with different characters.
We also learn Anakin catches on quickly with using the force like Rey also. Another thing is we learn Anakin doesnt really have a family and was abandoned there. As George Lucas just said how everything has a pattern. This would mean if Anakin is born from the Force so is Rey. Now I know what your thinking well what about Luke, Anakin and Padme' had him not the Force. Well my belief is since Rey was born after the battle of Jakku a lot of men and woman were killed meaning there would be no way for Rey to be conceived. Unless one of the Jedi's have a baby but that would be breaking the Jedi Code.
As Mantra puts it "There is no emotion, there is peace. There is no ignorance, there is knowledge. There is no passion, there is serenity. There is no chaos, there is harmony. There is no death, there is the Force."
Whats the opposite of death, life meaning the Force brings life. Which now coming to my conclusion this proves that the Force can bring life and since Rey doesnt have Parents that we've seen we can only assume the Force is what brought her to life.