Who knows if it's true, that if you and your partners blood type is NOT compatible, that you cannot have a child together?

if the mother does not receive the RhoGAM shot after her 1st birth, there after if she becomes pregnant and the baby has a different blood type than the mother, then the baby will die/miscarriage caused from the disease know as Hemolytic Disease of the New Born.

source: Anatomy & Physiology 7th edition by Patton and Thibodeau

not true!

There’s probably a missing piece to this information. Blood types obviously dont have to be compatible because otherwise the human species would have long died out. How would our ancestors have figured out who was compatible?

I think you’re referring to the RH compatibility. Two people who are RH incompatible generally are not able to have children together without medical intervention. This is because the body of the female will sense the opposing RH bloodtype in the fetus and will see it as a foreign body or parasite and will attack it. This happened to my friend Terri. She is RH negative, her husband is RH positive. Together they had several miscarriages before discovering the reason. They now share two healthy children, though. She just had to get shots every month or so to keep her immune system from attacking the baby. So to answer your question, yes and no.

If 1 of the partner has present of antigen in he/her blood plasma and the other has no antigen, different blood group do not matter is just the rhesus factor which is the present of antigen or not she would definately need the RhoGAM after first child birth if not she will misscarriage the second baby and others to come it doesn’t mean they can get married

no that is not the reason at all. yes it deals with the RH but if it was their 1st child and kept having miscarriages then theres a different reason. Hemolytic Disease of the Newborn in which your referring to only happens after the 1st child is born(they need to have a child) and then after their 1st child is born they are suppose to(the mother) is suppose to receive a shot of RhoGAM which prevents antibodies of forming antibodies against Rh+ antigens. now what you said if they had a child already and never received the RhoGAM shot (for some reason) then yes there was a very high risk of having Hemolytic Disease of the Newborn.