I have a idea and it's set in the middle of season 6.
KIra along with Bashir is down on the Bajor visiting Shakkar for offical Busines and also because a flu has broken out on the planet which is why Bashir is along. Kira ad Shakkar go pay their respects to a grave which we find out was a child she had a miscarage with Barei years ago and she has never really told anyone except a few people like Odo,Shakaar and Bashir for medical reasons. She begins to feel a what she thinks is the flu but then see's a baby girl who was the baby she didn't have. Bashir finds out she is having a hallucinations and this starting to happen to millions of Bajorans on the planet.
Bashir calls for a quantine of the planet and starts looking for a cure and he finds out it is the Blight. The Dominion planted it their with those Vorta faculitars during the 6 episode war arc that started the season. While the disease is deadly it's not as bad as it was with the other aliens because of Bajoran DNA but the main thrust of the story is she keeps hallucinating about her baby only everytime she see's the hallucination it's her child at a older age and she starts talking with her. While Bashir rushes to find a cure we find out Kira never had any desire to have children and feels guilty about her death as if it was her fault for having those wishes and thorugh the episode she comes to terms with those feelings. Bashir finds the cure. The episode ends back on the station where she talks to Odo about her experience. How she feels about possibly having children and she doesn't want one. While this doesn't start their romance it sort of deals with a issue that has always been in the back of Odo's mind about how he can't give her a child.
Jason