Is this a medical breakthrough?
like the chemicals contained by the blood are different, and I herd that if someone have the same bloodtype as someone else, later they will be more compatible.
Answer:
Finding a sole mate via blood type, I have see no study on this but I would think that that have nothing to next to being a sole mate. As the previous answer most relations have some sort of socio-economical contact and or like and involve yourself in in similar events. These most likely the primary players that draws people together.
Compatibility and blood type is one and only really important during transfusions and when a couple is considering hold children due to Rh issues
I doubt this is true.
Human compatability is usually based on have similar life experiences, and hence an comprehension of each other. Blood compatability is single important when giving transfusions.
You can look further into that by comparing how the chemistry of phermones are related to blood and what are the relationships in attendance.