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Why do girls live long?

It’s a well-known fact that women tend to live longer than men. On average, women live about 5-6 years longer than men in developed countries like the United States, Canada, and the countries of Europe. This gender gap in life expectancy has persisted over time and across many different cultures. But why do females live longer than males? There are a variety of biological, social, and behavioral factors that contribute to women outliving men.

Biological Differences

There are a few key biological differences between men and women that help explain why women tend to have greater longevity.


One major factor is hormones. Estrogen, the main female sex hormone, seems to have a protective effect on longevity. Estrogen helps regulate the immune system and reduces inflammation in the body which can lead to chronic diseases. Testosterone, on the other hand, may suppress the immune system and lead to more inflammation.


Research has shown that women may also just be genetically predisposed to live longer. Women have two X chromosomes which provides them with a “back up” if a mutation occurs on one X chromosome. Men have only one X chromosome, so harmful mutations have a greater impact. The second X chromosome in women provides genetic redundancy which allows women to better recover from harmful mutations.

Biological Robustness

Some researchers believe that women may have more robust biology overall compared to men. This allows them to better recover from disease and illness. For example, women have been found to have stronger immune responses to infections which allows them to survive acute illnesses better. Women also tend to have more body fat than men which provides an energy reserve during times of sickness and injury. This extra biological “buffering” in women helps promote longevity.

Behavioral Factors

In addition to innate biological differences, there are a number of behavioral factors that contribute to the gender gap in life expectancy.

Risk Taking

One major factor is risk taking behavior. Men are more likely to engage in high risk behaviors like smoking, drinking excessively, and dangerous physical activities. These types of risky behaviors increase men’s susceptibility to deadly accidents, substance abuse issues, and chronic diseases like cancer and heart disease. Taking unnecessary risks leads to far more men dying prematurely than women.


Men are also disproportionately affected by violence. According to the United Nations Office on Drugs and Crime, almost 80% of homicide victims globally are male. Violence from accidents, homicides, war conflicts, and suicide kills far more men than women worldwide. Exposure to violence reduces overall life expectancy.

Health Behaviors

Studies show that women are more likely to engage in positive health behaviors than men. They are less likely to smoke, more likely to exercise, and more proactive about getting health screenings and checkups. Preventative healthcare allows early detection and treatment of diseases. Men are less likely to go to the doctor regularly or maintain healthy diets. Poor health habits shorten men’s lifespans.

Social Factors

There are also a number of social and cultural factors that negatively impact men’s health and longevity.

Occupational Hazards

Historically, many men have worked in dangerous jobs like mining, construction, firefighting, and the armed forces. These occupations expose men to hazardous conditions, accidents, and injuries – all increasing mortality risk. Although workplace safety has improved in recent decades, occupational hazards remain higher for men.

Access to Healthcare

Access to medical care also influences gender differences in longevity. In many developing countries, women utilize medical services less frequently than men due to gender discrimination, restrictions on female travel or finances, and sociocultural norms. Lack of access to healthcare negatively impacts women’s life expectancy in these nations. However, in most developed countries, women actually utilize more preventative services and outpatient care which improves longevity. Men in these regions are less likely to seek healthcare which reduces lifespan.

Leading Causes of Death

The leading causes of death differ substantially between men and women. The top causes of death for men include heart disease, cancer, unintentional injuries, and stroke. For women, the primary causes are heart disease, stroke, lung cancer, and breast cancer. Heart disease occurs earlier in life for men due to different risk factors like smoking. Men are also more susceptible to preventable accidents. The distribution of causes of death contributes to a shortened male lifespan.

Historical Trends

20th Century

The gap in life expectancy between genders used to be much smaller. At the turn of the 20th century, this gap was only about 1-2 years in favor of women. As living standards, hygiene, and medical care improved, the gender gap widened. By 1950, US women lived on average 7 years longer than men. Then by the late 1970s, this difference increased to 7.8 years. Medical and public health advances helped increase overall life expectancy, but had an even greater impact for women.

21st Century

More recently, this gap in life expectancy has started to narrow again in many countries. Since the 1970s, men have begun living longer while women’s longevity gains have slowed. The reasons are complex, but likely involve increased smoking rates among women and narrowing of gender differences in risk behaviors and occupational hazards. However, even with these changes, women’s life expectancy at birth worldwide remains about 4-5 years longer than men on average as of 2020.

Key Takeaways

Some key takeaways about why women continue to outlive men:

– Biological factors like hormones, genetics, and innate robustness promote longevity in women. Estrogen provides immune and inflammation benefits while genetic redundancy helps women recover from mutations.

– Behavioral factors give women advantages as well. Women tend to take fewer risks, engage in less violence, and practice more preventative healthcare.

– Social and occupational hazards like dangerous jobs and reluctance to seek medical care negatively impact men’s lifespans.

– Historical trends show women pulling ahead in life expectancy during the 20th century due to medical advances. But the gap has narrowed slightly in recent decades.

– Despite some convergence, women on average still live 4-5 years longer than men worldwide due to a combination of biological, social, behavioral, and environmental factors.


The gender gap in life expectancy has multifaceted explanations. But the predominant biological, social, behavioral, and healthcare access factors give women an edge in longevity over men. Public health initiatives to curb violence, reduce occupational hazards, and encourage positive health behaviors in men may help narrow this gender gap. But research shows women will likely maintain a longevity advantage for the foreseeable future.