ABSTRACT
Hippocrates, the father of Western medicine, was aware that individual differences (polymorphism), such as eye colour, baldness and certain illnesses, could be passed on from parents to their children. As early as the first few centuries AD, the Jewish Talmud recognised that if two male infants within one family had bled to death following circumcision (due to the condition now known as haemophilia) then subsequent boys should be exempt from circumcision.
