It’s been a long time since I read the Barsoom stories, but IIRC, the red martians were oviparous, like the Tharks. IOW, they laid eggs. John Carter and Dejah do have children in later stories.
Well...just damn.....my daughter is gonna feel vindicated....IIRC, fertilization in a lot of species is on the eggs after they are laid.....ewwwwwww...such a smokin hot hottie and no game in town....