No, dom/subverse dynamics aren't like omegaverse 2nd genders. They aren't (usually, there may be one or two dom/subverses that decide to bend the rules a bit, but I haven't seen them) for reproduction. That's why in the dom/subverse, having a dynamic is usually considerably rarer or dom-sub pairs may usually consist of male and female pairings in stories where they aren't rare. Personally, I hope not many writers take a reproductive approach to dynamics as it is kinda the biggest difference between the two. However I also understand why someone might want to make dom-sub pairings be able to reproduce. Seeing the adorable babies is one of the most wholesome things about Omegaverse stories.