Males are born the weaker sex and are less likely to survive birth and infancy. That is why males are born at a rate of about 1.08 to 1 more often than females.
Whilst they do not last as long, those few that do make it into advanced old age are generally fitter than their female peers.
Before 1970, the reasons for male infant mortality were due to infections, and chronic degenerative diseases.
Recent advances that have improved infant mortality rates have mostly affected male survival rates since males were the most vulnerable.
So now we have weaker males than before surviving infancy and childhood too by the look of it - should we be expecting a more marked gap in life expectancy between the genders as these males reach the critical midlife years?