I once had an argument about blood types with a co-worker.
I have a negative blood type. DH has a positive blood type. Should we have children, that means I must get one of those rhogam shots to prevent my blood from forming antibodies against an rh+ fetus. I even had pamphlets from my ladybits doctor explaining this in great detail.
My co-worker tried to argue with me that you only needed that shot if the father is of a negative blood type, not the mother. She kept saying "you only need to get that shot if the father has a negative blood type! the mother's blood type doesn't matter at all since a woman's body automatically knows not to harm the baby!" She would not listen to me, even after I handed her the pamphlets from my doctor explaining the blood type factor and who needs to get the shot. She said "No, see, that's wrong..I'll google it and prove it to you!"
so she gets online, googles it..gets very quiet...and says "oh. wikipedia says that you do get the shot if you're the mother and have a negative blood type..so you were right, I guess."
She wouldn't believe medical literature directly from my doctor's office, but wikipedia proves everything.