Little is known about Obi-Wan's backstory, which is both a good and bad thing if you're banking on the theory that he's Rey's grandfather. On one hand, there's nothing that could definitively confirm that Obi-Wan fathered a child at any point (who would then have gone on to have Rey). On the other hand, fans of The Clone Wars animated series (which is considered canon) know that he definitely wasn't incapable of love. As this eagle-eyed Redditor points out, Obi-Wan openly admits his feelings for Duchess Satine in the show, going so far as to say he would've left the Jedi Order for her. The idea of him having a girlfriend or wife at some other point is something to be seriously considered.
