I know I'm O. Not sure of my titer. We had to type ourselves in our A&P class in college. Mom was an A+. Dad was O- but they had to titer him out X7 times to get a stable titer when he had surgery once. I suspect I'm a negative though because mom had a lot of difficulties with her pregnancy with me.
I tried to donate once but they wouldn't take me due to my medications and pre-existing conditions. I know 20 years ago when my mom needed a transfusion due to a bleeding ulcer, it was over 1000 dollars per bag of whole blood. I wonder what it is now cost wise to the patient?
Anyone watch Ancient Aliens? They had a segment some time ago about blood types. If I remember this correctly, there was a period of time where the only blood types in humans were A-, A+, B-, B+ and AB + and -. Then suddenly O appeared and nobody seems to know why it showed up or how it showed up in our genetic profiles but they insinuated that it was kind of a unique and odd ball blood type and people who have it are genetically 'different' from the average human.
When we heard it, DH looked at me and told me he knew it all along.....I'm an alien..