The idea that out of the billions of Bajorans on the planet(s), Dukat even ever saw in his lifetime (let alone spoke with, knew, or slept with) Kira’s mom is so outlandish as to be, for the most part, only the stuff of fiction.
I hate 'Wrongs darker than death or night' for this exact reason. I think it's one of the worst episodes of DS9. For me it's the ultimate example of small universe syndrome. The episode would have worked just fine if it had turned out that Kira's mother was just a comfort woman for Cardassians, the addition of a relationship with Dukat was totally unnecessary. Kira didn't need any more reasons to hate Dukat.