My parents had a story that the first time my dad ever met my mom's father, he opened the door and immediately asked dad, "What are you gonna do if my grandson needs a blood transfusion?!"
Grampa was a WW2 vet, an airplane mechanic, a Methodist and Freemason. He and my grandmother were pictured all my life as these ogres who opposed my mother's JW conversion and her marriage to my father. I never spent a lot of time with them, never got to know him, and only had a (not)Thanksgiving dinner with my grandmother towards the very end of her life. They were by no means perfect or even necessarily good people.
But episodes like that one were always told a certain way by my parents. As kids, we soaked up the lesson quite well: Blood transfusions are bad, and we have to withstand persecution from family about our beliefs.
And that is so completely irrational to me now. Why can't your beliefs withstand criticism, and re-examination? Why the persecution complex? Dad, why couldn't you just get off your high horse and admit this is wrong?
Now, I have to study with my wife about this because of her years of indoctrination. Because we want to have children, we have already accepted blood fractions to that end, and indeed, what am I going to do when our son needs a blood transfusion?