Arnold's hair

I guess this is a little outside the scope of training but I was just curious if anyone knows if Arnold Schwartzenegger’s hair is his own or the result of some kind of surgery or drugs. You’d suspect that a man in his fifties with a history of steroid use would be showing some signs of baldness by now, but he has a full head of hair. Is he just one of those lucky few without the male pattern baldness gene or does he have a great toupe?