To actually wax serious about the subject matter for a moment I’d not completely discount the possibility because they’re alien life forms with whatever blah blah biology we don’t understand. They are clearly mammals, as evidenced by their nipnops the size of our heads, but since all we’ve seen are the “males” it’s possible that they’re more functional than those of, say, human males and maybe they actually do have fully-functional asexual reproductive systems and you know what I’m actually going to end this discussion here because I just became the unfortunate victim of the mental image of Gruul angrily breastfeeding Skulloc and Grulloc with Durn the Hungerer wailing in the background and this is honestly something I never, ever wanted to think about.