It’s a fact that has become almost invisible in its familiarity: women, on average, outlive men.

Globally, the life expectancy at birth in 2023 was 71 years for men compared to 76 for women – a consistent five-year gap that has remained unchanged since 1950. In the United States, that gap has grown even wider, with men dying 5.3 years earlier than women in 2023 – nearly triple the gap seen a century ago. Across all OECD countries, women live longer than men, with the gap varying from 3 to 10 years.

But why? The answer is not simple. It’s a complex interplay of biology, behavior, and social forces. And importantly, as experts increasingly argue, this gap is not inevitable.

The Biological Hand We’re Dealt

Men are biologically more fragile from the start. One of the leading theories points to the fundamental difference in our chromosomes. Females have two X chromosomes, while males have one X and one Y. Because males have only one copy of the X chromosome, any harmful mutations on that chromosome are more likely to have an impact, since there isn’t a second copy to compensate. There’s also the “toxic Y” hypothesis, which suggests the Y chromosome itself may carry genetic elements that negatively affect health and aging.

Then there’s the role of hormones. Women have higher levels of estrogen, which is believed to have protective effects – particularly for the heart. Women develop heart disease about ten years later than men, and men are 50% more likely to die from heart disease. Men also have lower levels of “good” cholesterol, further increasing their cardiovascular risk.

Evolutionary biology offers another piece of the puzzle. A 2025 study published in Science Advances that examined over 1,000 animal species found that in species where males compete intensely for mates – investing energy in traits like large muscles, antlers, or fighting rivals – males tend to have shorter lifespans. The biological resources needed to grow big muscles or compete for status come at a cost to longevity. In more monogamous species, where this competition is reduced, males live longer.

The Behavioral Choices That Cut Lives Short

Biology, however, is only part of the story. Men consistently make lifestyle choices that undermine their health. Across OECD countries, men smoke more, are twice as likely to engage in heavy episodic drinking, consume fewer vegetables, and are more likely to be overweight or obese. Women are 50% more likely to eat a healthy diet than men.

Risk-taking behavior is another major factor. Men are far more likely to die from accidents, violence, and other external causes. In fact, external causes – including suicide, accidents, and violence – account for 31% of the top ten causes of premature death among men across OECD countries. Men made up 67% of preventable injury-related deaths in 2023. Men also die from suicide and homicide three to four times more often than women. While depression is more commonly diagnosed in women, men die by suicide at far higher rates – accounting for about 80% of suicide deaths.

Some of this risk-taking may have a biological root. The frontal lobe of the brain – the part that controls judgment and consideration of consequences – develops more slowly in boys and young men. This may contribute to higher rates of deaths from things like drunk driving, biking without helmets, and violence.

Men also have more dangerous jobs. They far outnumber women in the riskiest occupations, including military combat, firefighting, and construction work.

The Social and Structural Factors We Overlook

Perhaps most importantly, men’s shorter lifespans are not just a matter of “bad choices.” There are powerful social and structural forces at play.

Men go to the doctor less often. While 84% of women had a wellness visit in the past year, only about 74% of men did. About 44% of men report they do not attend their annual wellness visits. But this isn’t simply stubbornness – it’s shaped by how boys are raised and what society expects of men. Masculine gender norms discourage vulnerability, emotional expression, and help-seeking. As Derek Griffith, professor of population health at the University of Pennsylvania, put it: “We think about men’s health as a problem of men’s misbehavior… We haven’t looked at the social and structural drivers, and commercial and political drivers”.

Healthcare systems themselves often fail to engage men effectively. Men are screened for fewer cancers than women – women are routinely screened for breast and cervical cancer, while men are only routinely screened for colon cancer. The marketing of tobacco has historically targeted men, and there are fewer public health campaigns focused specifically on men’s health issues.

Social connection also matters. People with fewer and weaker social connections – which tends to include men more often than women – have higher death rates. Married men tend to live longer than single men, likely benefiting from the “protective effect” of being in a committed relationship.

A Gap That Can Be Closed

The good news is that this gap is not fixed. Over the past decade, most OECD countries have actually narrowed the gap between male and female life expectancy. This shows that policy and behavior change can make a difference.

But some countries are moving in the wrong direction. The United States, Mexico, Latvia, Israel, Iceland, Canada, Costa Rica, and the United Kingdom have all seen the gap widen in recent years. In England, the government is developing its first-ever men’s health strategy, recognizing that men’s poorer health outcomes should not be treated as “inevitable or self-inflicted”.

Closing the gap will require addressing all three factors: biological vulnerabilities through better medical care, behavioral risks through public health campaigns, and social and structural barriers through policy changes. It means creating healthcare systems that better engage men, challenging cultural norms that discourage men from seeking help, and addressing the commercial drivers – like tobacco and alcohol marketing – that target men.

The longevity gap between men and women is real, significant, and has deep roots in biology, behavior, and society. But it is not destiny. With focused attention and meaningful action, we can help men not just live longer – but live better.