Female longevity. If you check the CIA World Fact book ( 2009 edition) you will note that female life expectancy is greater than male life expectancy. Overall the average life expectancy for males is 64.8 years while female life expectancy is 68.76.
The UN Fact book for 2005 - 2010 offers slightly different numbers. Here we find an overall life expectancy of 67.2 years with men at 65.0 years and women at 69.5 yers. Of course these numbers include both industrialized and non-industrialized nations and the discrepancies among nations can be great.
Japan is the nation with the greatest longevity. The average is 82.6 years with males averaging 79.0 years and females 86.1 years - females living 7.1 years longer than their male counterparts. At the other end of the longeivty spectrum, there is Swaziland where average human longevity is 39.6 years with male's at 39.8 and female's even less at only 39.4 years. But this is an unusual situation in global data about human life span. As a whole females live longer than males. And in the more 'developed' or industrialized countries the gap between the sexes increases. (Some believe this is due to better health care and fewer women dying in childbirth.)
Anecdote: As a child I used to visit our local cemetary with my Grandmother. It was a rather large cemetary and as we walked to our family plot. I was often struck that a number of headstones from the 19th century listed the name of one man with dates showing a long life span. Under that was 'beloved wife' with the names of 2 or 3 women with successive dates. Then there were some headstones that showed women outliving their husbands - usually with a war memorial plaque on the grave. For me this was an education in 'life and death' realities of that past time.
But anecdotes are not science and scientists have been reflecting on the reasonsfor the disparity in life span between men and women. Their discussions range between NATURE and NURTURE or genetics and culture.
There are some who argue that female longevity is built hormonal. Statisticians
have discovered that women who live the longest are women tend to have children late in life.
Researchers from the University of California, Davis and the National Health Research Institutes of Taipei, Taiwan found that female life expectancy appears to be related to a Woman's age when giving birth to their last child. Using records from a cohort of French Canadian women of the 17th - 18th centuries these researchers found that female longevity of those who bore children appeared to vary depending on the age of their youngest child. This study has appears to offer evidence of the notion that hormonal activity is a possible predictor of female life expectancy.
Other theorists claim that female longevity is based on genes. They point to studies which show that female longevity a tends to run in families. It may be genetic. Having a long lived grandmother seems to be an indicator for a longer human life span of her female grandchildren.
Recently there has been some discussion of the implications of social roles in differences between the male and female longevity. Some writers claim that since child raising has been mostly the work of women in a family , women need to live long enough to not only raise their children but to be helpful in the child raises of their grandchildren. And so nature has made this possible by providing for greater female life expectancy.
Of course, one wonders that if this is true, whether the recent social development of more fathers being involved in day to day child raising activities will increase their longevity. Or, on the other hand, if the increasing geographical separation of grandmothers from their children and grandchildren will begin to reduce female life expectancy.
Other theorists explore the notion that because women's lives are so devoted to nurturing in their adult years, they are given greater post menopausal years so as to have time to engage in the social world and develop other aspects of their personalities. Men do not need these 'extra years' since they have been engaged in the social world of business and commerce most of their lives. . Such theorizing about human life spans is interesting. But if you want to read more about human longevity and its implications for our lives....and our planning for our future years, click on:
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