Logistics in health care 101?

Universal health care. Hypothetical. And yet this is a very common situation. Guy A. works out everyday, healthy, 25, doesn't smoke, has no history of any diseases in his family. Guy B. 25 ,Drinks every night, smokes like a chimney, never works out, and his family is full of past cancers and diseases and such. Is it fair that guy A. has to pay for guy B's terrible life style?