How many people would change their moral beliefs, or stance, under certain circumstances?

This was prompted by another new question, asking about stem cell research. There are many fundamental Christians who are violently opposed to such research because they’ve believed all of the rumors that involve aborted fetuses.

30 years ago I heard that Jehova’s Witnesses are opposed to blood transfusions for some religious reason.

So, if the only course of action that is available to save a person’s life is a blood transfusion, or a procedure developed through stem cell research, etc., should that person sign a waiver saying they’d rather die, or let their loved one or child die? How many do you think just might change their minds when they’re staring death in the face?