Speculation…
Shmi “There was no father. I carried him, I gave birth, I raised him. I can’t explain what happened.”
Palpatine using abilities “some consider to be unnatural” conjured this child of the force within Shmi (a random slave of no importance). Palpatine is secretly Anakin Skywalker’s father (and acts like it throughout the PT).
Palpatine - having survived his fall down the Death Star chasm (much like Luke survived the Cloud City chasm - it rhymes!) used those same abilities to create Rey, again within a random junker of no importance. Palpatine is Rey father, she’s of the same line.
Seems at least possible?