Everywhere in the world women live longer than men - but this was not always the case. The available data from rich countries shows that women didn't live longer than men in the 19th century. What's the main reason women have a longer life span than men? And how the advantage has grown as time passes? There is only limited evidence and the evidence is not strong enough to make an informed conclusion. We recognize that biological, behavioral and environmental factors play a role in the fact that women have longer lives than men, however, we do not know how significant the impact to each of these variables is.

Independently of the exact number of pounds, we know that a large portion of the reason women live so much longer than men in the present but not in the past, is to have to do with the fact that a number of fundamental non-biological factors have changed. These variables are evolving. Some are well known and relatively straightforward, like the fact that men smoke more often. There are others that are more intricate. For example, there is evidence that in rich countries the female advantage increased in part because infectious diseases used to affect women disproportionately a century ago, so advances in medicine that reduced the long-term health burden from infectious diseases, especially for survivors, ended up raising women's longevity disproportionately.

Everywhere in the world women tend to live longer than men
The first chart below shows life expectancy at birth for men and women. We can see that all countries are above the line of parity diagonally. This implies that a baby girl from any country can expect to live longer than her brothers.

This graph shows that although there is a women's advantage across all countries, differences between countries can be significant. In Russia women have an average of 10 years more than men; in Bhutan the gap is less than half one year.

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The female advantage in terms of life expectancy was lower in countries with higher incomes that it is today.
Let's examine how the advantage of women in terms of longevity has changed over time. The next chart compares male and female life expectancy when they were born in the US from 1790 to 2014. Two points stand out.

The first is that there is an upward trend. Both genders in America live longer than they used to 100 years ago. This is in line with historical increases in life expectancy everywhere in the world.

Second, there's an increasing gap: The female advantage in terms of life expectancy used be extremely small, but it grew substantially during the last century.

It is possible to verify that these points are also applicable to other countries that have data by selecting the "Change country" option on the chart. This includes the UK, France, زيوت تطويل الشعر (glorynote.com) and Sweden.