Rey Hatched from an Egg
There is actually a theory that posits Rey doesn’t have parents, but rather was hatched from an egg. Oddly, this theory has more backing it up than some of the wilder ones (looking at you Snoke is a dead youngling fans).
The idea comes from a story in Marvel’s “Poe Dameron” comic series. In the story, the people of the planet Ovanis protect a sacred blue egg called a Creche Egg, which they believe houses the galaxy’s savior. The odds that Rey hatched from said egg are next to zero, but weirder things have happened in “Star Wars.”