(September 2001) People undeniably live longer today than they did in the past. But for behavioral, biological, and other reasons, not everyone benefits equally from the gains in life expectancy.

Women outlive men in almost every society. In more developed countries, the average life expectancy at birth is 79 years for women, 72 years for men. In less developed countries, where high maternal mortality reduces the difference in longevity, women can expect to live an average of 66 years, compared with 63 years for men.

The map below illustrates the gender gap in life expectancy worldwide. In only a few countries in Asia (Afghanistan, Nepal, and Papua-New Guinea) and Southern Africa (Namibia and Zimbabwe) do men outlive women. The female advantage is highest in Russia, 13 years, because of the increase in mortality rates for men during most of the last four decades.

Gender Differences in Life Expectancy

Source: PRB, 2001 World Population Data Sheet.

The interesting aspect of the life expectancy gap in more developed countries like the United States is that it rose throughout much of the last century.

Gender Differences in Life Expectancy at Birth, United States, Selected Years, 1900–1999

Source: PRB, 2001 World Population Data Sheet.

What explains this persistent difference? Part of the answer is behavioral. Men are more likely to smoke than women and are also more likely to take risks, making them more susceptible to life-threatening injuries. Biological differences also help to explain women’s higher longevity. Scientists believe that estrogen in women combats conditions such as heart disease by helping reduce circulatory levels of harmful cholesterol. Women are also thought to have stronger immune systems than men.

Researchers have found that the gender gap in life expectancy is smallest for the wealthy and highly educated, suggesting that broadening access to quality health care, diet, and other advantages can help men achieve a level of longevity closer to that of women.

Jennifer Jones, now a research assistant for Westat, Inc., was domestic programs fellow at PRB from 2000 to 2001.