What I don't "get" about the rumors is that I typically hear a line like "Desert females never get big enough to breed," but I've seen lots of pictures of BIG desert females that looked perfectly capable of breeding size-wise.
I think I read that Pro-Exotics did have one female get egg-bound and need to have the eggs aspirated and removed, but that could've been any morph; also seems like that would've been more of an issue of uterine tone than of size.
Basically, I'm nowhere near convinced that desert females have issues, based on the paucity of evidence one way or the other. (Not like the many pictures I've seen of caramel girls on slugs.Booh.)