Major spoilers for Star Wars: Battlefront II's story campaign and speculation for Star Wars: The Last Jedi.
We won't find out the true identity of Rey's parents until next month's Star Wars: The Last Jedi, but the campaign for Star Wars: Battlefront II may tease that reveal. The story follow the exploits of Inferno Squad, a small team of elite Imperial soldiers led Iden Versio. Their adventures begin near the end of Return of the Jedi and eventually finds her and squadmate Del Meeko switching sides, defecting to the Rebellion.
After the Rebellion's decisive victory at Jakku, which effectively ended the Empire for good (its final remnants retreated to the Unknown Regions of the galaxy, where the First Order was eventually founded), Iden and Del fell in love, settled down, and had a daughter. Del was later captured by the First Order, interrogated by Kylo Ren for the location of Lor San Tekka and the map to Luke Skywalker, and then killed by Gideon Hask, a former member of Inferno Squad who had become an officer in the First Order.
However, Iden's fate and that of her daughter was left unresolved. Right before his death, Del warned Hask not to go after Iden or his child, who he described to Kylo Ren as "dangerous". This plot thread has been left dangling ahead of extra DLC set for release around the release of The Last Jedi, which has got fans speculating the dangerous daughter is in fact Rey.
Rey's parents are a total mystery, with popular contenders including Luke, Han and Leia, Obi-Wan, and just about anybody else of a suitable age (or, in the case of Jyn Erso, not even that), although the current thinking is they're actually separate to the main Skywalker narrative. As such, including their story in Battlefront II ahead of the release of The Last Jedi would be an incredibly savvy and subversive move on Lucasfilm's part.
It definitely could fit that Rey is Iden and Del's child. The timeline of when she was conceived isn't made explicitly clear in the game, which is crucial; Rey was born about twenty years before The Force Awakens, ten years after the end of the post-Jedi portion of Battlefront II's story. The real clue is Del calling his daughter "dangerous"; could he and Iden have discovered their daughter was Force-sensitive, recognized her power and ultimately decided to hide her from the First Order for all their sakes? It definitely could connect to the movies in some ways: Kylo Ren's knowledge that there was a girl out there somewhere who is "dangerous" would line up with his anger and subsequent interest in Rey in Episode VII.
But as much as Rey has in common with Iden's daughter, there's nothing to confirm it. Indeed, it seems very unlikely that Lucasfilm would green light divulging the identities of Rey's parents in a video game instead of saving such a major revelation for one of the movies; especially as the daughter name-drop is so obvious. Given all we know about the direction of the sequel trilogy, it feels like a very static turn. While those involved with the game have said the upcoming DLC expands the story in a semi-spoilery way, it surely wouldn't be something so fundamental. It's more likely Luke's compass, confirmed by the creators to be a major connection with Episode VIII.
It's entirely possible Iden really is Mama Rey, but when you consider how Battlefront II is just a small part of the galaxy, it feels rather unlikely.