Nazi eugenics
The Nuremberg Laws of 1935 made anyone who wanted to get married get tested for genetic disorders. The goal of this rule was to make sure the "Aryan race" would stay "pure," without people with disabilities in it. While dating, everyone was encouraged to question their dating partner carefully about whether anyone in their family ever had a genetic disorder. Members of the Schutzstaffel'' (SS) were ordered to carefully interview possible marriage partners to make sure they had no family history of hereditary disease or insanity, but to do this carefully to avoid hurting the woman's feelings.  They were told that if they had to reject the woman for eugenic reasons, they should do it politely and not upset the woman.