Some of my Scandinavian friends explanied to me that in Viking times if a baby was born deformed or defective it went straight into the sea. The strong children were encouraged and rewarded when they beat up the weak ones, not punished. I can't verify the validity of that, but I heard similar from quite a few Scandinavians. In Denmark I definitely witnessed this type of mentality. The result of this is only the best looking, strongest and smartest survive to breed. Tribal selective breeding.