The female advantage — that is, the tendency of women to outlive their male counterparts — has been long viewed as an established scientific fact. Data today shows that a newborn baby girl’s life expectancy in the US is slightly more than 80 years, while a newborn boy’s hovers at about 76 years. The question is, is there a basis to believe that this is more than just circumstantial coincidence? Are women really biologically wired for longer lifespans, or are there various unrelated — and often irrelevant — factors at play?
Infant Mortality Rate Impacts Life Expectancy
In most countries around the world, the infant and child mortality rate is higher in boys than in girls. In under-developed countries, where the infant mortality rate is high, the gap between male and female life expectancy widens dramatically, while in wealthier countries, where there are fewer infant and childhood deaths, the gap is much smaller. This indicates that a large factor of the female advantage seems to be merely a reflection of childhood mortality rates. Once a person has outgrown childhood, does a woman still have a higher life expectancy than a man?
The Behavioral Aspect
For many years, studies indicated that the female advantage was due to a number of non-biological factors. Men are more likely to lead unhealthy lifestyles, and therefore their life expectancy drops. Men are more often in stressful, high-pressure, or even dangerous jobs; more likely to smoke and drink; more likely to engage in reckless or dangerous behavior; and in general less likely to take care of themselves. But this theory may be disproved by a cursory glance around today’s society. For example, the number of women smokers has actually risen in the past few decades. American women today struggle with the same unhealthy life-shortening habits that men do. However, the female advantage persists.
The Biological Factor
It was once thought that higher estrogen levels present in women help reduce harmful cholesterol from circulating in the body, leading to lower incidence of heart disease in women. But then scientists discovered that administering estrogen to older women (whose estrogen levels decline as they age), was actually found to increase the risk of heart disease!
Some have suggested that women’s menstruation during their reproductive years is the cause for their longevity. Loss of blood means loss of iron, and while iron is vital for our health, too much iron can increase the risk of cancers and heart disease. Because men don’t have a natural way to eliminate iron, men often have higher iron levels, and therefore more frequently suffer from these often fatal illnesses.
Many studies indicate that perhaps it all comes down to the Y-chromosome, only present in men. It begins to die out in some men as they age, leading to cancer or premature death. Some theories suggest that because a woman has two X chromosomes in place of one X and one Y, the second X can take over if the first X is damaged.
While statistics indicate that the female advantage certainly exists to a greater or lesser extent worldwide, everyone agrees that a predisposition toward longevity is by no means a guarantee. The so-called female advantage won’t provide protection against poor lifestyle choices and lack of self-care. The best ways to ensure a long life remain what we have known all along: making healthy food choices, sleeping well, and exercising regularly.