I don't know how "special" RH- blood is, but I can say for sure some of these things apply to me. Low blood pressure, low body temp, and I have trouble with magnetic/electrical fields, just to name a few. I would like to see more research done on the cause of this mutation and the physiological differences between people with the different blood types. It's the next logical step after the mapping of the genome, after all.

As for the breeding thing, the way it was explained to me was simple. I have 2 kids. My first turned out to be AB+, and my second is the same as me, B-. They gave me the Rhogam shot with both pregnancies. The doctor said it wasn't that big of a deal, the shot negated what small chance there may have been for any problems, but that if I hadn't had the shot with my firstborn, my body may have developed antibodies to the rhesus positive blood in my uterus. During the initial pregnancy, even without the shot, this would not have caused any issues. It would only be if I then got pregnant again with an RH+ child - at that point, without the shot, my body would recognize the fetus as a foreign invader and attempt to expel it. As the previous poster said, this does not even happen 100% of the time, even without the shot, so I would take issue with the idea of being different species. I would, however, like to know why this happens at all, ever.

Fascinating subject, with a ton of misinformation out there, and not many facts. The Neanderthal theory makes the most sense to me, so far anyway, as to how it came to be.