And?
First, because they might not have a biological child does not necessarily mean they would choose to be childless. Most couples I know start by trying to procreate. When that doesn't work, they choose adoption. If you look at the episode, Dax and Worf were already exploring artificial insemination, albeit with their own genetic material--they were already working their way down the list of alternative methods to making a family. Even what Bashir was proposing in TOTP was merely offering the possibility of procreation, something which does not itself erase the rather bleak prediction he made earlier in the episode. Second, the need to find a host for the symbiot would probably take precedence, and I could see Worf, grudgingly, accepting artificial insemination as a means of producing an offspring that could carry Dax after Jadzia passed away, especially as their access to medicine would be restricted by their primitive condition.
