This character driven Odo episode is sort of a remake of third season's "The Abandoned" with Odo again exploring parenthood. Yet here the story works better because of a richer plot (a sequel to second season's "The Alternate") and two notable guest stars. There's James Sloyen, who returns as Odo's father-figure, and then there's a glass of goo, making its debut as Odo's adoptive son. Both are wonderful and set the stage for Auberjonois to carry the show with what might be his best performance as Odo, who must confront his past, present, and future on the most personal of terms.
Meanwhile, Kira prepares to give birth in a comedy runner which throws together O'Brien and Shakaar (the latter making his final appearance) for some awkward scenes played for laughs. ("Next time you have a baby, leave my girlfriend out of it") It's really just a filler plot to set up the birth of the child, and it's kept appropriately short, doing what it has to while not overstaying its welcome.
With the birth of the child and lasting consequences for Odo, "The Begotten" stands out as one of DS9's more memorable episodes.